I took prozac yesterday for the first time and I hated it. It made me feel buzzy, I lost all concentration, just felt very odd, and it has caused SEVERE insomnia. I literlally sat up all night, no sleep whatsoever. I have decided it is NOT for me, i have no intention taking it again, but my question is how long until that single pill wears off? It took it around 3 o clock yesterday afternoon. It is now 9:41 in the morning and it is still going, when will it wear off?