Fetal HB declining, waiting to MC

Hi all- from what I understand, I have a very very high chance of miscarriage. Knowing this and being in limbo for so long has been very emotionally draining. For anyone who was in a similar situation, I am just curious how long it took.

Went for scan at 6 weeks 4 days - saw gestational sac, yolk sac. We were told we had a 50/50 chance.

Went for scan 7 weeks 4 days- saw large yolk sac (greater than 8mm), fetal pole measuring 5 weeks, 5 days, HB at 91. Being 2 weeks behind doesn’t add up based on tracking ovulation and when I got my positive pregnancy test.

Went for scan at 8 weeks 4 days- yolk sac decreasing, baby measuring 6 weeks two days, HB 78 (we could see it but not hear it this time).

The doctor said this is likely a miscarriage but wants us to keep waiting 😢 I should add I’ve had terrible nausea so this has been brutal. Thanks for any insight or help!