I messed up, what should I do?

I'm not sure what it is you did, but if it's something to do with a girlfriend or boyfriend, see if you can have the chance to apologize to them for what you did. If they don't respond to that, then just leave it go for a time and don't try to call or text them. The old saying is if you love something let it go, if it comes back to you it's yours, if it doesn't, then it wasn't meant to be. That's helped me a lot in my life.

A heartfelt apology should suffice.