Hey Josy!
Find what makes you happy and refreshes you. For me, I like to sit on my patio and just breathe. Nature brings me back to life. Sometimes, I like to just go for a drive in local fields with the windows rolled down so I can smell the world. Also, when I'm way stressed, I find that listening to music like Nine Inch Nails or Marilyn Manson while driving and turning it way up and screaming out the songs with them, seems to really help me get it out. It destresses me. But, everyone has their own destressers. You just need to find what makes you feel refreshed.
Try to sit in a quiet place or lay in bed or something with the lights out. Whatever is comfortable. Breathe slowly in and out. Don't think about anything at all. Concentrate on nothing but your breathing. When thoughts come up, concentrate on your breathing more and don't entertain the thoughts. Do this for at least 10 minutes and you will feel better. Don't be discouraged if you can't unwind at first. Just keep doing it until you do.
Hope that helps!