I've found that if I take phen early in the day I'm not as sleep deprived. If I take it at 11:00 then I can't sleep. I end up taking it at 8 A.M and am not as sleepless as I am taking it at 11:00.
I just started phen yesterday. I didnt have trouble falling asleep but I didnt sleep as long as I usually do. I dont know if thats good or bad. Going to try some sleepy time tea tonite though.