How Will I Feel?
If your thyroid levels rise (hyperthyroidism) your whole system may feel speeded up. Your heart may race and you may feel nervous with shaking hands, increased sweating, insomnia, and anxiety. If your thyroid levels fall you could feel sluggish, tired, run down, depressed, and experience muscle cramps and constipation. In either instance your thyroid gland in the front of your neck may enlarge slightly and may feel mildly tender though extreme pain is uncommon.
http://www.allthyroid.org/disorders/pregnancy/problems.html