Michelle-
I have been on Nortriptyline for migraine prevention for several years. Initially, the dry mouth and tiredness were a real problem. To alleviate the tiredness, I began taking the medication at night. Give it some time before you rule it out as an effective treatment. For me the dry mouth disappeared after several months. The negative long lasting effect was weight gain.
You have to weigh the plusses and minusses. For me the decrease in migraine freqeuency was worth the wieght gain.
Good luck!
James