Bicornuate uterus

Hi ladies! I am wondering if any of you have experience with a bicornuate uterus. I had my daughter who’s three now without any complications with the uterus, my midwife says they must not have noticed it with her. But this pregnancy, they noticed it right away at my 8 week appointment. Well fast forward to 29 weeks, they gave me an ultrasound and turns out she’s growing on track at 3 pounds, and I’m measuring 4 weeks ahead. Now, I am 33 weeks and I’m measuring only 2 weeks ahead. they want another ultrasound at 35 weeks, to see if she is still growing and on track because thanks to my heart shaped uterus, it could stop her from growing and have to come out. Well I have been checking my weight on my scale at home and I have lost 3 pounds since my appointment 2 weeks ago. I’m worried because I should be gaining weight, so that I know she’s gaining the weight. I know I gotta be patient and just wait for this ultrasound but I’m just scared for the outcome when I’m loosing weight and don’t feel like I’m getting bigger and went from measuring 4 weeks to only 2 weeks ahead.