What you are describing could be seen as an anger management problem. But it seems that your bad moods and negative thinking are a recent development. If that’s the case, it’s more likely that you are suffering from depression. Depression sometimes shows up as irritability and anger. This is especially true when a person dwells on things as you have described. That’s called “rumination.” I’m on the side of the people who tell you that you need help. Your thoughts and feelings are hard on you. Your behavior is damaging your relationship.
When I searched the web for alternatives to therapy for rumination, I found quite a few informative articles. I suggest you do a similar search. Of particular interest to me is work that is being done with mindfulness. If you don’t have access to therapy, you might look into whether there are some meditation classes offered in your area. Meditation helps us let go of thoughts and generally calm down. It won’t be easy at first but with practice, you may find that it gives you considerable relief.
I wish you well.