hmm series of incidents you say. It's hard to speificy but if i think about it, it was a matter of "ignoring her" "looking for any reason to complain" "being hot headed all the time" "not letting go when she apologized for something minor she did (where i had the tendency to tie that thing to my finger and be mad for days while she was suffering that i was mad at her) and then i snapped out of all of this and everything was fine. So i'm starting to think, as another user stated, that i need treatment for mental health
These things aren't mental health issues, they are behaviour issues.
Your depression needs to be addressed separately. You have used it as your Get Out Of Jail Free card for too long, without doing a single thing about it expect take your moods out on your g/f.
Three days into this "month", you still haven't done anything about it.
Why is that?
You've written reams about what you want, but haven't taken any action that is different to what you've done or not done in the past 6 years.
All it takes is one phone call to your GP & you will be on the road to a diagnosis (if you actually are depressed) & treatment.
People don't stonewall, complain, pick fights, or refuse to apologise because of depression. They do it because they think they have the upper hand, & can get away with it.
Maybe have a long think about how many years you have been giving your g/f a hard time, & why you are only now thinking about improving your behaviour because you risk losing her. Then improve your behaviour by finding a proper therapist who has a lot of experience handling self-justifying bullshit, & seriously get to work on the reasons underlying your less admirable behaviours.
You will be a happier man for it, eventually.