Chemical pregnancy but still bfp?

Hello ladies

Last week I got a bfp on Sunday, went to the doctor to confirm (hcg was at 13 so very early) on Wednesday but then started spotting and bleeding bright red Wednesday night which continued with very heavy bleeding, terrible cramps and many clots (sorry if tmi). I had blood drawn over the weekend but have not heard the results yet. I had a pregnancy test left over and decided to take it to make sure it was negative since I haven’t heard from the clinic. It has been 5 days since the bleeding started and my test today was even more “positive” than last week prior to bleeding. I am by no means hopeful (I had a miscarriage last year @ 8 weeks and the process of bleeding was similar to that) but I am wondering how long it takes for hcg to show negative? With my MC last year my levels dropped almost immediately when the bleeding started. Any experiences out there with this?