I doubt this has no input from your end, nobody is "that" good to allow something like this to go on with out wanting to.
Are you trying to do an etching solution?
I'd personally go on my Steam account, block and remove him from my friends' list if I was you, to be honest. This is definitely not friendship at all. Always remember than only you are in control of your life, not him. The only thing we can control is ourselves, not the others, so he just can't do that, if he can then that means that you're letting him do it. Keep your eyes open. And welcome to TWHL!
Dude, I'm going to try and say this as kindly as possible, but that's not a friendship. That's a hostage situation. I get that you like the guy and at times he can be kind and caring, but for him to go off on you for taking a few moments to yourself... That's borderline psychotic. And the fact that he has caused LASTING phobias as well? Relationships and friendships break apart all the time and both sides get over it. Hell, once school is over you will likely lose touch anyway, if not immediately then certainly over the coming years when you're both off doing different things. Telling him that you don't want to hang out any more might cause him some grief in the short term, but drawing this "friendship" out doesn't exactly seem like it's going to do YOU any favours.