IPhone 5 sleep button not working?

It's completely not working is there any way to fix? I really don't like the idea of being without my iphone for 2 weeks.

Is it turned on? If so, this is what you need to do.
Go to Settings. Then go to the General tab. Scroll down the Accessibility. Scroll down to AssistiveTouch, and turn it on. It will show a small box, with a circle in it that stays on your screen, in the lock position or not. You can also move it around your screen boarder. To lock your phone, touch the circle, then touch Device, then touch Lock Screen.
No more problem. If you need to turn it off, simply let the battery drain. To turn it on, plug it into a wall.It'll automatically turn on once it's charged for a while.