Especially if you gained a lot of weight?

My weight gain has been super steady since the end of first tri (1 lb/wk) and then in the last 2 weeks I've gained almost 4 lbs at 18 weeks! It's probably a combination of feeling so awful that I could only eat carbs and having some major constipation from my nausea meds, but now I'm really worried that I'm going to end up with GD and/or gain 50+ lbs.