I'm finding it hard to fall asleep please help?

Hey everyone so I finished work about around 9pm it's now 11.33pm and I have to be up at 5.30am so I can get ready for work again. I'm finding it really hard to fall asleep I've been tossing and turning in bed since 10pm. I don't know if I should go outside for 5 minutes to get some air or whatever but I need help. I need to sleep.