Is this normal at 7 weeks?

I’m 7 weeks pregnant today and I feel like a bump appeared overnight! My belly feels bloated and a little sore, it seems almost swollen. I had an ultrasound yesterday and everything looked good, and the said it was only one baby but my HCG is high and I’m convinced it still might be twins and they just missed it somehow. I’ve read that that does happen especially with early scans. Don’t get me wrong, I didn’t have a flat stomach before being pregnant, but my husband and I agree that this seems visibly bigger and it seems unusual to be starting to show at seven weeks. This is my first pregnancy to ever make it this far along. Is this normal to be starting a bump now?