We just don't know right now. Some antibodies could work better than others, so for some people it could mean yes and for others no. Could be different for symptomatic vs asymptomatic patients. Some antibodies could make the disease worse through ADE. Immunity is probably conferred for at least a couple months since we dont see a huge number of reinfection, but we dont know whether it trails off after a year or two or goes below an important concentration threshold since there physically hasn't been enough time since the start to measure immunity out to a couple years. In general, you're probably fine, but maybe not, and the test could also be giving you a false positive.