underactive thyroid
"I have taken Synthroid for 23 years.  The first 3 years I did okay on it but over the past 20 I started to feel losey.  I'm tired all the time and very irritable.  I've taken from .050 MG to .125.  I still feel bad.  It's been adjust at least 30 to 35 times through the course of 23 years. I feel totally helpless and hopeless.  My doctor will not change my thyroid medication."