I have this too but it's due to low iron/anemia. I'm assuming your doc checked you for that along with the thyroid? Also, your hemoglobin can be in the normal range while your iron stores can be depleted. Dehydration will make you tired too and since we j pouchers are prone to that make sure you're taking in enough fluids.

Me too...hate to say it but I don't have any idea why and no one else has been able to give me any good advice...
I have found that after going back to work in Sept and barely surviving the first month that the 2nd month is a whole lot better...I am up at 5:30am to get to work on time and honestly the first month had me in tears every day (in pain and practically hysterical) but as time goes by it does get better...I am going into month 3 and I can now get up with problem, run for the subway and survive the whole day without wilting at noon....
I am starting to think that my body got accustomed to my being at home all day and was exhausted from doing nothing (fine, not nothing...cooking, cleaning, shopping etc) because I was not 'under stress' like at work...and now it is getting used to its new normal and adapting just fine with only a few bumps along the road.
Sharon

Have you been tested for sleep apnea and the other associated syndromes (restless leg syndrome and periodic limb movement disorfer)that can keep someone from getting a good night's sleep? Iron deficiencies can contribute significantly to these disorders.

There are a lot of things that could be going on such as fibromyalgia which includes chronic fatigue and the ideas above. Please start out with a Rheumatologist to be checked out for autoimmune problems. There is a reason why you are feeling the way you are. You might want to do a search for fibromyalgia, chronic fatigue, sleep apnea, restless legs syndrome, or by your symptoms and see what you turn up on-line.

Have they checked your B12 levels. If you are low, it can really zap your energy!