Am i gaining more pounds than expected?

I am 29 weeks 4 dyas. I weighed myself last night before I went to bed, When I didnt feel full at all. My weight came to 150.6lbs. Im only 5'3". Before the pregnancy I was 117. Yes a bony little thing. Wearing a size "0" in bottoms. I know for sure I am not dont gaining weight. Is this normal? Will it have an effect on me after the baby? Will it be hard to lose? What should I do. I thought I was supposed to gain only between 20-25 pounds.