I walked in on my bf having with my best freind?

I was having my sweet 16 and was looking for my bf so when i looked in my parents room i saw my bf and my best friend having first i poured a drink on my bestfriend and slaped my boyfriend and then told then that i hated them the next rmy best friend texed me saying that she met for me to walk in on them what to do before i lose my mind