I had been taking 50 mg Amitriptyline for 3 weeks and suffered side effects, so my doctor had me quit cold turkey 3 days ago. Do I need to worry?

This class of med. is less prone to cause withdrawal trouble, so follow your doc's recommendation. If s/he puts you on Paxil, Effexor (venlafaxine) or even Cymbalta, be prepared to withdraw gradually if you quit in the future. These three are known to cause trouble in this way, which is why they are my last choices in this med category. Consult with a psychiatrist for a more definitive and personally relevant discussion.