Amantadine did not do a thing for my fatigue. I only took it for a few days, but I remember I felt really sick, had a headache. Had to stop.
The doc encouraged me to try it when my insurance balked at the cost of provigil - after they'd paid for it for like a year.
I had to go through hoops to get them to pay again. I'd had good results with it for some time, then it just stopped helping. I keep thinking of trying it again someday to see if it helps after taking a break.
I did have some headaches for the first week or two with provigil, but not too bad. And I'm so prone to h/a it was not a real issue - air gives me h/a, lol.
That was the only side effect, if it even was one, that I had. Good luck with it.