Baby bump and worried weight

Houa • Happily married 👦🏻👶🏻👶🏻| 18
Here's an update on my baby bump. Having a baby girl who'll be expected to arrive November 26. I'm currently 27 weeks 1 day. I feel huge. Just saw my doctor this past Thursday and he says my weight went up, which makes him sort of worried. This is my second pregnancy and before I got pregnant I was 245lbs. (I'm enormous, I know.. Still had some baby fat that I didn't lose from my first pregnancy.) on Thursday I was 270lbs, meaning I gained 25lbs already & that was my only goal for my entire weight. I'm scared she'll come out huge ! & I want a natural birth like I did with my son. (He came out 8lbs 6oz.) any suggestions to stop the weight gain or to help lose some weight gain? Don't wanna gain no more than 30lbs now .. I'm proportioning my food and drinking tons of water. I tried doing some exercise but that just put me in pain from back toward the front.