Weight gain issues

Someone tell me I'm not alone in this. I am gaining weight way too fast. I have hypertension issues prior to pregnancy, and am high risk. But I watch my salt intake and so far my blood pressure is ok and I don't have any swelling issues. But they checked my thyroid the other week and the levels are off indicating hypothyroidism. I had half My thyroid removed when I was 14 and when I had my daughter in jan 16 I didnt have problems with anything. I was super suck my whole pregnancy tho and lost 15 lbs prior to gaining any weight. I'm now almost 26 weeks and I have not been sick for weeks this pregnancy, I was hospitalized for dehydration and they switched my meds. The trade off is the weight gain. I don't eat a ton but I havent been able to eat well. Alot of bland carbs. Reflux has been killing me so alot of fruits and veggies are out cause they make me sick and burn to be thrown up. I'm freaking out. I feel like a failure. I'm losing my mind over this. Someone tell me I'm not alone here. Anyone who can offer any suggestions on food or light exercise..... Or relate????