Probably not. The best way to know for sure is to have your provider either listen to the heartbeat (not always heard at only 8 weeks) or repeat the ultrasound. Considering your recent miscarriage and partial mole, I can certainly understand your anxiety and think the best way for you to know what is going on is an ultrasound. Good luck!
Not necessarily but I would suggest calling your doctor and going to get your HcG checked and your progesterone.
At 8 wks the belly could just be bloating. I'm 8wk5d right now. My belly pouch is not consistent. I really thought it was just due to bloating or maybe I am relaxing it a bit more now because I can :)
If the cramping is significant, I would call your dr for sure. I've had some minor cramps but nothing significant.
Take care and congrats!!