You can sleep with your contacts on, but becuase they absorb water your eyes will tend to get dry so splash some water on them before blinking again normally, i mean just take a minute to wet them and do not attempt to just get up and ignore that they feel dry becuase the chances are the contact themselves may be dragged by your upper eye lid into the back of your eyes!

Sounds crazy but it happens, when it does do not be alarmed but again put allot of water in your eyes this time and try to open and close them until the contact falls out (over the sink), it normally will come out the first attempt., contacts are a phenomenon becuase you can splash water on them while they are perfectly on the center of your eyes but if they move around the back where they make contact with the eye lids they will tend to either go back to the center themselves or fold and fall out from the water you add to flush them.

Sorry for the graphic details but i intended to describe this in a matter to give people confidence that they can rest assure it is possible and the eyes also will not get damaged, but be sure you do not have them on more then 8 hours straight if you can avoid it., take a break for 5 minutes at least, headaches is all you will experience., this was from a eye doctor.