I really want to try modafinil again. I had two tablets over three days: half, half and whole. I could not see a difference between half dosage and whole dosage

I really want to try modafinil again. I had two tablets over three days: half, half and whole. I could not see a difference between half dosage and whole dosage (200 mg). I couldn't figure out what the effects were, either. Until about the end of the week, when I realized I hadn't taken a sip of coffee in three whole days! That was pretty unusual for me.