Belly doesn’t look bigger

I’m 15 weeks today exactly. My last ultrasound was at 13 weeks and everything looked great. I have a history of miscarriage though and for anyone who’s experienced pregnancy loss it’s hard not to worry about every symptom or lack of. My belly has been bigger up until this point but now over the last few days I no longer that feel bloated feeling. I also lost a pound. That’s really it. No concerning symptoms otherwise. I asked my doctor to do another ultrasound Bc my next one is not til the 20 week one and they said they wont unless there is a real problem bleeding cramping etc. , especially Bc insurance won’t cover another. At 15 weeks I’ve also gained 13 pounds but the weight gain has stopped now. Is this too much or too little? Thanks!