Also, you are not broken. No one is broken. If you’re breathing, you have the chance to make things better. No matter how bad it seems, it is possible to make it better. I’m sorry if that sounds cliche, but I truly believe it. “Every person is only one decision away from a completely different life”.
Writing is good. I have a whole book of writings for 15 years. Your text reminds me of it. Don't worry about any of this. You have to find what's going on inside your head. But I suggest you stop giving yourself bad names like "DontWannaBeMe". Talking too much about negative things enforces your vision of yourself.
Writing is good indeed, venting out frustrations in a positive way is a good thing. However its only a coping method. A good solution is cutting the triggers and developing yourself. Ask yourself what you want from life, and go after these things.