What are you actually doing to try to lose weight? I went from 125 to 212 being on a medication for my migraines. When I decided to lose weight, I didn't succeed because my idea of what an actual portion size was, was so off. I know many people on this site say you don't have to count calories, and technically you don't. But it doesn't change the fact that if you are underestimating the amount you are eating, losing weight is going to be extremely difficult, and gaining more weight is likely. That is what happened to me. I was eyeballing my portions, thinking something was a serving size, but I was actually eating 2-3x as much. I really just didn't know.
I'm an advocate of counting calories, but if you don't want to do that, just take what you would normally take, and cut it by 1/4. That, you can eyeball. Try that for a few weeks. If you find that you are no longer gaining, but maintaining, then you know you need to cut back just a tiny bit more. But if you see that you are losing by cutting out that much, then that's great.
You don't have to go on some fancy, restrictive diet. Being too restrictive can actually backfire by giving you really intense cravings. Just being in a calorie deficit is all you need.
Remember, you don't want to go on a diet. You want a sustainable way to eat for life that will allow you to take weight off, and then be able to maintain. Remember, the weight doesn't have to come off super fast, it just has to start to come off.
My headache specialist was THRILLED when I lost 12 lbs in 4 months when I last saw him, because up until then, I had done nothing but gain weight for the last 8 years. He told me I had to lose weight because I was in danger of becoming pre diabetic. Your doctor, I'm sure, will see that it's good if you just start moving in the right direction.
Good Luck!