Energy Drain Right Before I Play

[Ibanez8185]

(I am not really sure if this is the place to put this so Mods feel free to move it)

The last few months right before I start to play poker I get this energy drain where it feels like I could fall asleep. It really comes on sudden, and only when I'm about to play poker. I could have slept 8 hours and got up 2 hours before I play and I get the same feeling. It makes it hard to put in the hours when half the time I have to take a nap. I'm 21, I shouldn't need a nap all the time when I sleep fine at night.

Anyone else get this? or knows whats causing me to have a massive energy drain right before I play?

I have been thinking about getting caffeine pills and take them before I play. Not sure if this is a good idea or not.