Struggling to sleep

Laura
Hi guys. 
I need your help. I can't sleep past 3am(ish). Every night I go to sleep by about 10-11, but sometime just after 3 I'm awake. 
Well I say awake; I'm still shockingly tired. 
It's not 'cause I need to pee. Any suggestions on how to sleep through would be helpfull. I work full time as a nurse & this constant fuzzy state isn't good. 
Thanks.