[cathydownunder]

I would be very happy to take some of that sleep off your hands, would you like to swap for my insomnia?
Seriously though,you really need to have a full blood workup done, lots of things could cause excessive drowsiness/tiredness such as the ones already mentioned. It's a worry that you're so out of it you have so much dificulty being woken up, even after many hours of sleep.
I was on Effexor for 4 months, stopped it 2 weeks ago. It caused me to be hyperactive and one of the reasons I stopped it is because I couldn't go to sleep and am waking 4-5 x per night. I'm hoping that will improve once it's out of my system.
B.T.W. the Effexor also decresed my appetite for the first 2 months, how long have you been on it and at what dose?
Best of luck with finding an answer.
Cathy