my geko is acting funny

Question
my gecko has been very inactive and seems to be weak. he moves very slow and just sleeps a lot. he drinks water.. and im going to feed him tomorrow but im just very concerned.and his tank is the normal temperature. whats wrong with him?!

Answer
Hello Chelsey,
What kind of gecko do you have?
What is your setup like?  Do you have an undertank heater & a low wattage basking light on the warm end, with a cave or hide on top of the heater?  What are the temps in the tank?
What are you feeding him?  
What type of substrate are you using for him?
Do his stools appear runny or firm or smelly?
How long have you had him for?

Tracie