Sis, I know this is scary, pero please go back to your OB right away or go to emergency if you're having any bleeding, severe pain, or dizziness. Hindi dapat maghintay ng March 7 kung may red flags na ngayon.
This situation is really something na kailangan ng in-person medical guidance lang, ang combination ng delayed period, positive home test, negative serum test, at ang ultrasound findings ay needs careful monitoring from your doc who knows your full history. I can't say what happened sa iba because bawat case is different, pero your OB is already on top of it with the HERAGEST and follow-up plan, trust that, and call agad if anything changes before March 7.
Sending you lots of strength. This waiting period is really hard.