Welcome to Just Answer and thank you for the question.
I am Dr. Sohaib, a Medical Internist (who deals with diseases of all the organ
systems of body) and i will do my best to find an answer for you.
Sorry to hear about your problem.
Well, the best way to lose weight is by means of dietary control and exercise.
And both the diet and exercise plan need to be closely supervised and monitored by a certified dietician and a physical therapist, as together they can appropriately guide you regarding kind of diet and its types which will suit best to your needs, and various forms of exercises and the appropriate duration.
If these measures alone are not helpful, then pharmacological intervention can be done in the form of drugs that assist you to lose weight.
The only drug approved by FDA for weight loss is Orlistat (Xenical) which you can take to assist you in weight loss. You can ask your doctor for a prescription and discuss with him about this in detail.
Here is an article that i have searched for you; please click.
Furthermore, various bariatric surgeries are also an option but reserved only for resistant cases having morbid obesity. Click on this link for further details regarding these;
Most importantly an underlying cause need to ruled out that might be responsible for your weight such as hypothyroidism (already ruled out), cushings disease, and other diseases/drugs etc [surely your treating physician must have looked for these already].
I would have been worried too if i were at your place but let me reassure you that this is a treatable condition and carry a good prognosis, you just need to continue working over it continuously (in terms of diet and exercise) and discuss with your doctor the options i have suggested.
For excessive fatigue, Vitamin E 400mg daily along with Co-enzyme Q-10 supplements will be of great help.
Wish you good luck.
It was a pleasure assisting you and i hope my answer was helpful. I will
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only way i get credit for my time & expertise. Do not hesitate to ask any follow up
questions or clarifications any time.