I can't calm down. I can't go to sleep?

well, additional questions are to be asked in real life, in your area...
you sound like stressed or so- until proven otherwise...

Run 10 Kilometers every day...

start swimming

take a run

Breath in through your nose for three to five seconds, whatever comfortable. And then breathe out through your mouth, lips pursed, for twice as long. Repeat for a minute or two. It's not a huge change, but it helps.

try again

I take melatonin when I cant sleep. It helps calm me down. Get in a dark room, get comfy, put a movie in and relax. Good luck.

It used to happen to me, it was the fear of not getting enough sleep what caused me to be stressed at night. So just don’t worry, sleep will come when it has to come.

Progressive Relaxation can help tremendously. Give it a try and see for yourself.
https://www.youtube.com/watch?v=9OFklc7Cw7Y

You try to do a lot of things and you can sleep when you are tired.