You should call her/him up and tell how you feel... Tell her/him it isn't her/his fault, that you're sad and going through different emotions and need a break to think things through...
I don't know... I been single for over 5 years and im over 20+.
Lie to them, say it's not her/his fault. That he/she is perfect in all ways and you are the bad one. And that you don't want to hurt her/him even more,and you are breaking up.