I am also hypothyroid (for 20 yrs. already) and low in Vit. D. I don't know how old you are, but the menopause also does a number on you. I am considering a low dose estrogen and progesterone pill. My doctor said it could help.
Since they increased my thyroid pills, I do feel a bit improved. The pain is still there, but less intense. The Vit. D. I just started also.
I know your frustration with exercise. I used to exercise all the time, 5 days a week. Now because of my knees and back problems (herniated discs) I can't even walk. I try to do some yoga and very light walking, like 10 minutes just to walk my dog. It's so difficult, I know.
Lyrica isn't made for muscle spasms, but for muscle soreness and neuropathy involved in FMS.
Your thyroid could very well be causing some of the problems you describe...so could the diabetes and anemia. Until you get a clean bill of health (straightening out the thyroid, diabetes and anemia) you should only do low impact exercises (stretching or water aerobics is good).
If you have not had an MRI done, that may be something to consider to rule out other illnesses that can mimic FMS. Also, testing for Lyme Disease.
Hopefully, by getting your thyroid and other issues under control you will begin to feel much better in the months ahead. I pray this is the case for you.