You know....

My dad is a doctor and we've discussed this because I firmly believe that I may have a sluggish thyroid (have a lot of the symptoms) even though my blood tests consistently come back within normal limits. What he told me is that you can have a thyroid problem long before it ever shows up on the bloodwork, especially if you tend towards low thyroid.
If you really feel that you have a thyroid problem, my suggestion would be to go see an endocrinologist. Tell them your symptoms and hopefully they will be able to give you some good advice.