I know how scary it is. Even though my first few weeks were uneventful, I was scared all the time given that I had a mmc that was found out at 8 weeks in my previous pregnancy. I was pretty much living in constant anxiety. I am praying for you too! Bleeds in IVF pregnancies seem quite common - not sure if the added progesterone and meds play a role in it. I am sure your bub is fine given that the bleed's stopped.
Hang in there! No news is good news for now!