Get your thyroid tested and also test to see if you have PCOS (Poly Cystic Ovary Syndrome). PCOS will cause you to gain weight rapidly if you're not treating it. It's fairly common. If that's what you have, you will either need to go on birth control or metformin or both. I discovered I had it after I had to go off birth control pills due to blood clots I developed when I was sick in the hospital. I then gained 50 pounds in a year and a half and could not figure out why because I work out almost everyday and eat very healthy. I got really incredibly depressed too. Apparently being on the birth control all those years and then going off exasperated my symptoms and it became impossible to lose weight. I convinced my Gyno to put me back on birth control since I hadn't had any more trouble with blood clots and after a couple weeks of being back on the pill...I was finally able to lose weight again with diet and exercise. I don't wish this on anyone. I totally feel for you and understand your frustration. Don't give up...keep going to your doctors until you find the answer. I stopped going to a couple doctors that tried to tell me I probably wasn't cutting enough calories. I wanted to slap them. I felt like saying do you even know the hellish diets I've been torturing myself with?!! If eating 800 calories a day and running 10 miles isn't enough to lose weight...I don't know what is! Lol. Hopefully my experience will help others out there going through similar experiences.