Sleeping Issue

Since the last week, I've been having issues with sleep. Not to sure if I am over thinking things or it is something else. I've had about 4 hours of sleep a day mostly. And it is not like I am not trying to sleep as well. I get into bed at 10:30 PM, and I roll, twist and turn like there is no tomorrow. I feel so uncomfortable and uneasy that I just cannot seem to doze off. Do not get me wrong, I am sleep like hell, hardly can keep my eyes open, tired, yawning non stop... but I just do not seem to doze off.