Thank you for your imput. I would already consider my self "addicted" to physical activity though. I run a few miles at least three times a week, weight lift with a personal trainer on the days I don't run and do yoga regularly. It's frustrating because every professional I see or talk to seems to deduce that I am not active or am not practicing the right kind of diet. I also worked with a nutritionist regularly. All to no avail.
I am so sorry to hear about your experiences.
Given everything that you have been through, and accomplished, in a short period of time, I think there is every reason to be hopeful.
That being said, losing the weight is not going to be easy. Once you stopped the medications that made you gain weight you stopped gaining weight, but that didn't mean that you automatically started losing it, either.
I have a section on losing weight on my website, and in the process of writing that I identified a few things that were pretty consistently true across multiple studies. If you do the following things you are more likely to lose weight -
1. Get support for losing weight - this can be someone who is going to do it with you, and who you "check in" with every day, or a group, like Weight Watchers, or Overeaters Anonymous (I know, not relevant to you, but still worth considering).
2. Keep track of your weight and your diet. It can be hard, but just keeping track of how much you weigh and what foods you eat will tend to make you lose weight. The one tricky aspect of all of this is that weight measurement is a very inaccurate way of monitoring fat loss, which is what you care about. So it is quite easy from one day to the next to have an increase in your weight on the scale while you are still losing fat (this is because water is a much larger part of your body than fat)... prepare yourself for this and don't pay too much attention to day to day changes... track instead the general trend over several days.
3. You have several choices of diet that are about equally effective - a very low carbohydrate diet (Atkins), a very low fat diet (Pritikin), a portion control diet (Weight Watchers), and a diet focused on eating bulky foods (Volumetrics). The very low carbohydrate diet works somewhat faster, but you are more likely to regain weight with that approach... so if you do that pay particular attention to planning the transition from diet to "maintenance"... I think that there are a couple of reasons (clinical experience more than clinical research) for thinking that you might do particularly well with a very low carbohydrate diet.
4. In the long run, your success losing and keeping weight off will depend on also getting "addicted" to some kind of regular physical activity that is fun and that raises your heart rate (brisk walking, jogging, bicycling, etcetera).
Good luck!
Oh yeah, when I stopped taking the medication I stopped eating at night. I forgot to include that.