this post is more so pointed at Moezy-chan, since she's often calmed me down and helped relax my soul, but I really don't mind if anyone here wishs to help
That is very sweet and I'll be more than happy to help in anyway I can. First off, I would like to point the attention at you, and not your so called friend. As you've stated, you have anger issues, which are understandable, but you anger gets so out of control that your health is compromised. This can become very dangerous, and I would listen to your doctor about controlling your anger.
First, I'll give you an ultimatum. I myself suffer from anger issues, and it often gives me panic attacks, and upsets my ulcer. Long story, so I won't get into it, but for my remedy, I use healthy ways to release my anger. Such as writing. You say that you love to write, so put your thoughts down on paper. I would suggest paper and pencil instead of the computer. And when you get very mad, do 1 of 2 things.
1) Rip up the paper and throw it in the air
or
2) Crumple it up and throw it away
This will help.
Now to the main problem. From the information you've given me, it sounds to me that your so called friend has intrapersonal intelligence. If you know what this is, then you don't need the definition, but I'll state it anyways. Intrapersonal intelligence is when a person is in full understanding of themselves. They focus on them, and nothing else. When this happens, it's like the world is nowhere close to them. They are in a completely different world. I also have this type of intelligence.
If I'm right, not saying that I am, your friend is unaware of your feelings. He's too absorbed in his own. He may not even realize that he's doing it. This is where you come in. Type out a long, mature, reasonable e-mail to him. Tell him how you are feeling, and that you feel you are being used.
If I'm wrong, then he's simply a jerk and doesn't care about others feelings. In this case, you can take you anger out on me in a healthy way. I will be more than happy to talk to you. I have many lines of communication, and in this case e-mail is the best one. You can even take your anger out on me, because I won't feel offended. But keep in mind, you need to let this go. Your health and physical well-being are on the line, and that is more important than winning a fight. Try to relax, and if it doesn't work, I'll be more than happy to be your punching bag; so to speak.
I hope this helps, and that you'll feel better. Hang in there and pull through. And most importantly,
Zettai Daijoubu Daioh! Everything Will Definately Be Alright!