I find it really hard to sleep on Sunday nights, and I think its to do with the anxiety and worry about what I have to do the following week at work. Mind you, when I actually get to Monday (After about an hour of full sleep) I actually feel okay, I don't worry about anything, there's nothing to freak out about... hmmm!
I go through bouts of being able to sleep really well, for like, 8 hours, or sometimes have a game night and then have like, 4 hours sleep and still feel fine, but then there is like 2-3 weeks which will pass where I just cannot sleep, I toss and turn, I think too much about stuff which is bothering me, I hear noises then can't STOP hearing them. It's annoying!