Self harm at workplace

Sorry for a mess, but I need to vent.
Today wile being at work I decided to hit a wall with my head. It was very late and I was alone in the room. But my colleague I had a friendly relationship with heard the noise and came in. You know what he said? He said: "When you will be freaking out the next time do it outdoors". I shouted at him, that it's my head and I do what I want with it. And then he just exploded. He screamed profanities at me, told that everybody hates me and regrets employing me. Ironically, it was the thing that calmed me, it was as if I saw my own reflection and realized my ridiculousness. Then I decided to call my colleagues and ask if they'll be glad if I quit my job. Fortunately, I haven't done it. It pises me off so much, when people see you harming yourself and get angry at you for it. Like when my neighbor saw me hitting a tree for 10 minutes and said angrily: "Try hitting with your head".
Sorry for the rant.

The latter sounds more like a tease than ridicule.

Thank you for your rant. You helped me. I hope you can get your confidence back with your colleagues and that some of them wil be supportive.

People get frightened when others act in strange and violent ways. Frightened people say things in their anxiety they don't necessarily mean.

Are you sure hitting walls and trees is the best response you can come up with?

Having said that the thought of you suddenly deciding to leave your desk and hit the wall with your head does conjure up an interesting image.