Its normal as long as the baby is moving and growing and gaining weight. For my daughter i lost a total pf 30 lbs and for this pregnancy at first i lost 10 lbs and only gained 6, i will be 34 weeks tomorrow
Usually petite girls must gain uo to 30 pounds but like they said it depends on prrpregnancy weight and I'm pretty sure your doctor would've made that a big deal if it was something to be concerned about
Unless they are concerned about you or baby I would not worry. This is my third and I have lost 5 at this point and am 35 weeks ( I gained in the beginning and by lost 5 I mean I am 5 below prepregnancy weight) and they have not been worried. With my first two I gained 8 and 9 lbs. It depends on you and your starting weight as well as your dr. Some are adament about gaining others don't care as much as long as baby is measuring well.
I lost 1 and they seem concerned! It really depends though because I then went back in and had gained quite a bit and was measuring ahead. They will let you know if it becomes an issue.