I was born with congenital hypothyroidism and have been taking Synthroid (thyroxine) since. I have missed about 2-3 weeks of taking my dosage. Side effects?
Slow decline. This leads to subtle changes in metabolism and physical symptoms that may change so slowly you are not aware of them. Temperature sensitivity, changing energy levels, weight gain, constipation, etc.A blood test would likely show your brain sending out messages to turn on your non-working thyroid.