Blighted ovum and 50k HCG less than 6 weeks

UPDATE: my doc called and said the notes from the US tech mentioned a possible view of the yolk sac but it was hard to tell. He still doesn’t think this is viable but is having me come back in 2 weeks for another US. A good friend who is a specialized surgeon in OB thinks it could be a partial molar pregnancy.

So I’m waiting on my call tomorrow morning regarding my 2nd ultrasound. But I was told earlier this month I was having a chemical pregnancy after I got a BFP and my levels were only a 7 and I got my period immediately after I tested. I felt off for a week so took another test and it was positive again. Went for more bloodwork and the levels went up to 9000, waited 2 days and they went up to 20000 but i also got an ultrasound the day before the 3rd round of bloodwork and I was told the sac was empty. My doctor wanted me to go back again the following week (today) for bloodwork and they came back at 50000. According to my last period, I would only be 3.5 weeks along. I had another US today and the tech said the sac was still empty. I was told last week it was a strong possibility of a blighted ovum. The hcg levels and the potential weeks I’m along don’t line up to me. Anyone have any thoughts to this? My only other thought is my “period” wasn’t a period but maybe implantation bleeding. Based on the size of the sac last week, my OB said it was measuring around 5 weeks. I’m tired of going back for bloodwork but it seems like the doctors keep expecting my levels to drop by they haven’t yet..