I just told this person that I really like them, and they rejected me, I don't know what to do.
Thats unfortunate, did you tell anyone else about it before you confessed?
I told my best friend. I was really happy the day I told her, I made her swear not to tell anyone until I did it myself. But she didn't keep her promise. It's this kind of behavior that made her a terrible friend in my opinion.
Unfortunately feelings are sometimes unrequited. I'm sorry to hear about the rejection as well as your best friend not keeping your secret.
I hate my life, I feel like this is the end for me.
It's definitely not the end for you. Rejection is something everyone has to deal with at some point in life so don't dwell on it too much. It's just a part of going through life.