I've taken 20mg of amitriptyline for two years for chronic migraines. it's not heping, only ever helped for a few weeks at the beginning. my doctor is trying clonidine and said i can just stop the amitriptyline. i'm worried about withdrawal though?

Not all patients develop significant withdrawal symptoms and trusting your doc and reaching a consensus about a plan for possible withdrawal is still the best approach as you do not want to continue taking a chemical that is not helping and can cause significant side effects in the long range.

Am not surprised of amitriptyline failure as dose is far too low to be effective. You could abruptly stop without harm. Clonidine would be unlikely to mitigate migraine, and would instead consider BOTOX, CGRP items, or OTC's such as butterbur or riboflavin. Find an headache specialist for a second opinion.