How can I stop worrying about not going to sleep and actually get enough sleep?

Recently during the last week, I can't go to sleep. I fall asleep like around 3:00 am to around 7:00 am. I toss and turn around all night and now I feel tired. Maybe it's because I keep worrying about not going to sleep. I feel that this is not healthy for my body because I'm only getting about five hours of sleep every night. Any suggestions?