I was told by my doctor that I no longer needed my nortriptyline. I was taking 25mg for a year for frequent migranes and then my doctor increased my dosage to 50mg. I never gained weight on the 25 but gained weight rapidly with the 50mg. It is no longer helping my headaches so my doctor has told me to come off of it and has set up other testing for me to do. How fast will this weight come off?