After a miscarriage in first trimester mine was still positive for 4-6 weeks after. I think it'll disappear shortly. However if you have been sexually active with no protection you might have concieved again. You won't know for 2-3 more weeks tbh due to the old hcg and the potential new hcg.
Birth hormones that cause the lines (HCG) can stay in your system for roughly 4-6 weeks anything after that could be true positive, but if it’s positive after that time then suddenly negative that sounds like a chemical pregnancy
I did one 10 weeks after giving birth and it where a strong positive. I did one 3/4 weeks later and it was negative. Hope that helps xx