Unknowingly I took expired thyronorm 50mcg for 3 months. What will happen to me in the long run?

I didn't know it was expired because I never checked the expiry date. I experienced loss of appetite, vommiting, severe dry eyes of late. The medicine tasted very sour which was unusual as the medicine is itself tasteless.Today I was shocked to discover that the medicine expired on Dec 2010! What danger or chronic problems will happen to me in the long run? I'm of 21 yrs age on Thyronorm 50mcg tabs once daily since 2004.