I did not feel a difference on 150 mg for a few days after starting that med (I took it on two occasions years ago). I never took less than 150 mg. Consider giving it some time.

I must warn that both times I took that med I eventually became manic. My psychiatrist will never prescribe it for me again. I don't think that reaction is everyone's reaction. In fact, I once read that it is far less likely to cause mania than other stimulants.

I actually started to abuse the modafinil (Provigil) at one point. That was a very bad sign for me. Chasing mania.

Though I can't speak for others who have become manic on this med, it was unique in that my Provigil triggered manias would quickly end when I'd stop taking that med. That's unusual for me.