Three very basic tips.
1) Work to rule, stop all those unpaid hours. Anything that is left to do can be handed over, and if things get constantly left, then that is a MANAGEMENT issue to sort out and get more staff. You as an individual cannot do everything.
2) When you do leave the ward, leave work AT work forget the hospital exists. Live your life. Enjoy it. I love my career, but I love my personal life and health more. Work/life balance is essential.
3) EXERCISE!!!! I cannot stress this enough. Go to the gym, go for a run or for a swim, punch the hell out of a punchbag. Whatever it is you like doing, get some exercise, it is the best stress beater out there and has the added benefits of making you fit and healthy, keeping your body in the shape you want it to be in.