Hey there. I know we've talked a little bit though
PM. I would say that what you're doing is indeed self-harm. Self-harm isn't just about cutting; there are many forms it can take, including hitting oneself, be it with one's fists or with other objects. Self-harm is simply causing yourself harm on purpose. Many times people self-harm to cope with emotional stress or upset, and sometimes to feel like they are "in control," as you say.
You are not alone. I believe that you can pull through this; you are making great strides in reaching out to us here on TeenHelp. I am always happy to talk to you as best I can, as are many other people here. My hope is that, in time, and with support, you'll be able to find healthy alternatives to cope with your emotions. There's a great alternatives list in the sticky section of this forum. Perhaps that could give you some ideas. It's a good place to start, at the very least.
Take care of yourself, okay? I'm happy to listen whenever you need someone to talk to.