Best: I can't hold back my anger anymore. This implies that you have anger building behind a wall that is protecting the other person. It means that THEY are going to receive your anger, (or if you are talking about it to someone else, then the specific subject will be who you get angry at). I can't hold my anger anymore. I can't hold in my anger anymore. Think of a balloon full off water bursting and getting everything wet. These have no direction for your anger, so your anger is going to burst out and get all over everyone. Hope this helps^^

Either of the last two work. "Hold back" sounds more agressive.

"I can't hold back my anger any longer."