I can't understand my emotions right now and why I'm so angry, literally furious at my ex.

I ended it a few months back and we've spoken on text but not met up

After a little while when he contacts me I feel myself erupting inside and just getting so angry at him for. I can't even think about him without feeling like this

And when he texts I can't seem to stop myself bombarding him with texts about how angry and upset I am for all the crap he put me through and how much he hurt me even tho I've said it a million times

How can I make myself better