Im concerned about my obgyn

So what can i do to help keep my weight under control..i have cut back on carbs bread pasta an sugar. My doctor was Concerned my last visit. That is why i gotta go back sep 10. I failed my glucose test. So i gotta do the 3 hour test. I gained 20 pounds in 27 weeks. My stomach is also measuring big. It is getting harder to carry him. I still work walk watch what I eat. Does anyone have any tips? Help i don't wanna go back the 10th an he gets worried. My belly is out if control