Shit man.
That is beyond awful.

My advice: Get busy. Anyone would want to die if they sat around and allowed themselves to think about something as terrible as this.
I’m depressed like you are, for other reasons but that hate you have inside you isn’t going to go anywhere unless you let it out.
And although you could show your ex-friend what karma looks like, by repeatedly bashing his head in, you would then secure a fate of misery (and prison time) and your life would end up in ruins.

It’s going to take a while, but you need to accept what happened (meaning to accept you will need to never speak to those two awful people again) and move forward into a new venture. I suggest you beat the holy hell out of some pillows on a daily basis, or take up weightlifting or something similar, or else you may end up in a state of rage where you do something stupid.

The best thing can do is focus on making this a non-issue. Make those ****s see that you’re far better than them. Don’t allow this to break you, because they would take pride in that. F*ck them man. They’re as good as dead to you now. I know that’s hard to accept, but it’s the only way out of this mess.

Go do something big.