I felt extreme fatigue after taking levothyrox 50mg, and usually i dont feel extreme fatigue like this, is this a side effect???

No: Not an expected side effect of that medication, BUT... people can have what we call paradoxical reactions to medications. THey have an opposite response to the medication than what we would expect. Please discuss with your treating provider. Hope this was helpful. Best of luck. Dr R

Thyroid treatment: It is hard to answer your question without knowing all your history. What was thyroid tests before/after taking the 50 mcg? If you were indeed hypothyroid, levothrox treatment should make you feel better, although the changes along the way can be bumpy.