I have lost almost 30 lb and I'm only 11 weeks...
I'm almost 31 weeks and Ive only gained 4-5 pounds my doctor said I was fine I'm not really showing that much either
I'm 15+3 and I didn't get sick at all and I've only gained 2lbs its normal not everyone gains a lot of weight. If your doctor isn't worried you should be. But you'll gain more weight towards the end. I started my bump at 13 weeks and now I'm pretty big for 15w twice the size I was with my first bit still only 2 lbs all just fluid and baby.
O believe me girl i had the same "problem" now im almost 24 weeks and have definitely gained the weight i was wondering about. You will gain it in ur fifth month definitely