Is stalled weight gain in pregnancy normal?

I am currently 18 weeks pregnant. During weeks 2-14 I gained 10 pounds. (Probably due to a 3 week vacation and too much eating out) However, since I got back I have not gained an ounce in the past 3 weeks. Those being weeks 15-18. I always eat when I am hungry, and I keep it healthy except for a serving of dessert 1-2 nights a week. Is it normal for my weight gain to stall like this?