My girls are 7 weeks old already, for the past 4-5 days I feel great, …

My girls are 7 weeks old already, for the past 4-5 days I feel great, only my head sometimes spins, before that I constantly felt nauseous and now it's like I'm not even pregnant, and sometimes my belly feels pulled down. Should I go for an ultrasound?! I'm so worried... I don't know what to do...