If you are having 7-8 hours of uninterrupted quality sleep, then there is nothing you need to worry about. For some people, however, the requirement of sleep is much lesser. If you are waking up on your own and do not feel sleepy for the rest of the day, then I think you are in good shape.
However, if the above is not true , then anxiety
are possible causes of your symptoms. Anxiety can also be due to hyperthyroidism
or excessive dosage of synthyroid. Please get a thyroid profile and ask your physician if the dose can be reduced. If you have other symptoms like feeling low or guilty, lack of appetite
or eating too much; please see your physician. You may require an evaluation so that proper treatment can be instituted.
Hope this helps