Hi missjewelz~
I'm 58 and I did finally get my metabolism rolling....though it took me almost 3 years to do it. My much younger son, in his early 20's at the time, stopped a med that caused him to gain a huge amount of weight and within weeks he was back to his usually skinny self. I would imagine age can factor in, as it does with most things related to body and health. The other possible factor is that he got himself off the medication very quickly....after several months. Whereas I allowed the doctor to more or less browbeat me into continuing to take it for several years....not appreciating me questioning his decision, it seemed. Wish I had taken myself off it much sooner. So....length of time on it could very well factor in also.
But if I, at 58 and on the med for several years...could get my metabolism up and running again....so can you, believe me. I had the exact same fears as you....that I was doomed to stay that weight due to a damaged metabolism.
Now....this is just me, in terms of what I did. Apparently, these medications can affect the HAP annex (hypothalamus, adrenals, pituitary) in various ways. Since these are all glands in the endocrine system....I surmised that a metabolic (rather than a calorie counting) eating plan would be more likely to help. But....I did not have success right off the bat....and in fact, struggled for almost 3 years. I did Atkins and could not get the ketone sticks to turn.
And I was very experienced with the Atkins diet, having used it years ago to lose all the weight from 3 pregnancies (and kept it off until this medication packed on 65 lbs.).....and getting frustrated, it hit on me to go to a low carb site and ask for advice. And long story short, after trying some of the suggestions, it turned out that for me, there was now a huge problem with the use of artificial sweeteners.....which had not been a problem the last time I'd done Atkins. I had to go down to zero packets for a week, then gradually increase it to maximum of 3 packets per day.
Later, when I hit stalls, I used calorie-cycling to keep my metabolism rolling. It seems to be functioning quite well now....which I am so grateful for.
I certainly can't say I know the secret to getting the metabolism rolling again. But although the endocrine system is very complex, I believe that the best thing to try is a metabolic diet rather than a calorie-counting one, especially if you are already having trouble losing weight by watching what you eat/counting calories. I would try a strict low-carb induction period for a few weeks and see if that might just do it for you.
deena