Yeah, on that, it's called 'Rumination' if you are looking for the google key word to research it more. I've done a bit of research on this, as I ruminate a lot too and it has always affected my sleep. Does anyone have any good tips or sources on how to stop excessive rumination and just fall asleep? The only good things I have found are an exhausting amount of exercise or beer.

Yep, I learned about rumination from some therapy I had about a year ago.

I'm very far from being an expert so take what I say with a pinch of salt and see a professional therapist, if you can afford it.

It sounds pointlessly glib, but the answer is to stop thinking. It felt very unsatisfactory for me. I'm naturally a 'thinker' so there was a tendency to think that if my problems are caused by thinking, they can also be solved by thinking. I had to accept that this isn't true.

With practice you can begin to learn to gently redirect your thoughts to something else. Don't rush it, you mind will naturally wander back to rumination. But you can slowly get better at steering your thoughts away from it. It's a skill, a muscle that needs to be exercised.

This is basically what mindfulness is all about, although I didn't have much joy with the guided meditation exercises. I'm going to return to them and try again at some point.

Also, there's nothing wrong with getting there through an exhausting amount of exercise. It helps for me too!

For me, the rumination went hand-in-hand with being self critical. Being kind to yourself is another skill that needs to be practised.

Hope this is helpful in some way.

Cutting out all sources of caffeine (I had to; developed an allergy) and taking fast-release melatonin have lately made a tremendous difference for me in falling asleep.

I've had this same problem and have largely solved it. Here's my write-up:

Sleep is underrated. It improves our health, memory, mood, immunity and more. Here are some ways to improve your sleep and get to sleep on time.

BLUE LIGHT

    Flux: This program dims the blue light output from your monitor as the sun sets and brings the blue light back as the sun rises. Blue light is a natural signal of daylight that causes our body to produce less natural melatonin. Melatonin causes drowsiness. Flux can be disabled for color sensitive work. https://justgetflux.com/



    Cell phone apps: There are plenty of cell phone apps which have this same feature. I use Twilight for android. https://play.google.com/store/apps/details?id=com.urbandroid.lux&hl=en 



    Sunlight in the morning: Leave your blinds open while you sleep. When the sun rises in the morning it will naturally wake you up early and help establish your sleep cycle. 



    Tape over any unnecessary blinking lights 

NOISE

    Less abrupt noises: You'll sleep best if there aren't any abrupt light or noise changes. White noise can help drown out any sounds that would disturb your sleep. You could play a white noise sound from a site like 

A Soft Murmur: http://asoftmurmur.com/

or

RainyMood: http://www.rainymood.com/

You can also use other noises like the "wurr" of a fan.

CONSISTENCY

    Consistency is key to sleep. Humans aren't able to bank sleep well. For example, trying to catch up on sleep missed during the week by sleeping in on Sunday isn't very effective. Even if you can't go to sleep at the same time each night, waking up every day at the same time will quickly put your body on a good sleep schedule and make you fell more rested overall. 

SLEEP AIDS

    Melatonin: Melatonin is a hormone naturally produced by the body in response to sundown. Modern artificial lights can disrupt this process. It is sold over the counter and is non-addictive, unlike other sleeping medication. https://sleepfoundation.org/sleep-topics/melatonin-and-sleep                                                                                                                                                                  
    Ear plugs: These are great for dulling noises from inconsiderate family members or roommates while you're trying to sleep. I still can wake up to an alarm even if my earplugs do stay in all night.                                                                                                                                                                                                                                                                                                              
    Read a book: Reading is a great way to spend time before bed to get sleepy and take your mind off of the day's stress. 

DISTRACTIONS

    Cell Phone: Cell phones often require a lot of hand movements, uncomfortable head positions, and bright lights. Avoid looking at your cell phone in bed. To make yourself get up at the first alarm in the morning, plug your phone in out of reach of your bed so you have to stand up to turn off the alarm. 



    Computer: Computers are also distracting just like cell phones. Cell phones and computers are so interactive that they can keep your brain busy and stave off drowsiness. 

BODY COMFORT

    Heart rate: Avoid strenuous tasks right before bed. To go to sleep you're going to need to let your heart-rate drop to your resting state. 



    Eating: Don't eat right before bed. It may make laying down uncomfortable. 



    Drinking: You want to be hydrated but not so much you'll need to get up for the bathroom in the middle of the night. Put a glass of water on your bedside table so you don't have to stand up if you are thirsty in the middle of the night. If I ever wake up at night I take a sip of water and plunge right back to sleep. This water is good to hydrate first thing in the morning too. 

BED

    Launder your sheets frequently: This is easy and makes the bed much more comfortable and hygienic. You spend a lot of time in bed. How many hours would you wear clothing before washing it? Washing pillow cases often helps mitigate acne as well. 



    Use a blanket and a sheet: Too many people don't have sheets on their beds properly. A sheet will help you regulate your temperature by adjusting how much of your body is covered by each thickness of bedding. Tuck that sheet in at the foot end. Tangled sheets can make uncomfortable lumps in the bed. 



    Don't do other activities in your bed: Reserve your bed as a place where you sleep. Do homework, use your computer and do other tasks elsewhere. This way you can condition yourself to associate your bed with sleep so you'll get in the right mindset as soon as you lay down each night. 

CLOTHING

    Loose fitting clothing or none at all: don't sleep in jeans, tight bras, etc. Let your skin air out. Let your muscles relax into positions your clothing might normally prevent. 

PREPARATION

    Plan ahead: Get yourself ready for bed ~30 minutes before you intend on sleeping by brushing your teeth, changing clothes, and getting some water. 

RELAX YOUR MUSCLES

    Stretching before bed relaxes the body and the added flexibility helps to eliminate discomfort. 



    Progressive Muscle Relaxation: Flex and relax each muscle group in order from your head to your toes. https://en.wikipedia.org/wiki/Progressive_muscle_relaxation

CONTROL YOUR MIND

    Sometimes I can't sleep because my mind races with thoughts. This is worse if those thoughts are stressful. I like to write things down so I can forget about them for the night. 



    Tell yourself a story: To distract yourself you can tell yourself a story as you fall asleep. Establish characters with backgrounds, talents, and motives and then send them on an adventure. Pretty soon you'll be exhausted and give up on story as you drift to sleep.