Migraines? Related to amitriptyline, Levsin, Imodium?

I just started to get headaches over the summer. I was referred to a headache specialist. I had to keep a headache diary and saw him twice. Could not tell me why I was getting them. No patterns. So annoying. I have had two migraines now this year. Scared me a bit as the other headaches were a 3 or 4 on a scale 0 to 10. I have taken Imitrex for them but it seems to upset my stomach. I'm not having any major stress or anything in my life right now. Have you had any headache side effects from Amitriptyline, Levsin, or Imodium? I have been taking these medicines for years now...