I am not a doctor but it sounds like you are getting too much Synthroid. You may need to have your TSH levels checked again. They can change rapidly (within 3 weeks). My endo was looking for .5 - 1.5 for the TSH. Any lower than that and you are becoming hyperthyroid due to too much medication. I would also be aware of symptoms of a thyroid storm. They are:
Rapid heart beats
Greatly increased body temperature
Chest pain
Shortness of breath
Anxiety and irritability
Disorientation
Increased sweating
Weakness
Heart failure
Here is the full article:
http://www.emedicinehealth.com/thyroid_storm/article_em.htm