*lurking from January 2013/3rd Trimester*
I started out weighing 212 and lost 5lbs!! When I was 20 weeks I was back up to 212lbs. I'm 32 weeks now and according to my last appointment I've gained 11lbs, 1lbs a week since 20 weeks.
I would not worry about it unless your DOCTOR is worried. Your body knows what it needs to do and during the first trimester the baby is not really needing *food*, he/she is taking nutrients from other places. Good luck and your doctor will know your weight record.