Gestational sac & neg HCG level

Michelle

I am so confused right now. I got my BFP on 1/19/2021, but on 1/28/2021 I noticed my pregnancy test started getting lighter & lighter. On 2/2/21 I started bleeding for 3 days like my normal period. By 2/5/21 it completely stopped. Went to OB/GYN on 2/8/21 & had labs done & my beta was 5 & a gestational sac could be seen on sono. Had labs done on Wed. & Fri of that week and I am less than 3. Seen dr again on 2/15/21 sac is still present despite my beta being less than 3 & now I am having positive opk test. 🤔 How is that even possible? I am so confused right now. Has anyone else experienced this? What is gonna happen, or can happen in this situation?