33 weeks unwelcomed weightloss

Hi ladies! I am 33+1 today and I am frustrated because even with a calorie increase 2 weeks ago, I can't stop losing weight. I had great weight gain and was 136 lbs at my 31 week check-up. At my 32 week check up my doctor was fairly upset that I was down 9 lbs. Now that I am at 33+1 i am down to 125 lbs. I am eating as much as I physicallg can, even getting up once or twice in the middle of the night to eat more. Anyone else experience anything similar? If so, were you able to figure out something to help keep weight?? Thanks!