Hey OP.  Sorry to hear your going through a tough time.  Often times in relationships (even long term healthy ones) there is a break down in communication, and for most this occurs after what people refer to as "the honey moon" phase.  For me this has typically happened between 1.5-2 years.  We become less conscious of our actions and words and slip a little closer to our auto pilot... I've been in the situation before, I honestly consider it a rite of passage for relationships and it's at this point where you make the choice to develop beyond, or you sever ties.  Sadly, the latter is usually the default most people resolve to... But sometimes it's best (although never easy).  

It's important for you to make this choice for yourself.  Your girlfriend too.  If you both make the same decision, wonderful - from there you can both start to cement your new foundation together,or you can seperate (hopefully amicably).

To assist with the new foundation I recommend you take a look into 'Love Languages' by Gary Chapman, I think there may even be an app too.  Read it with your girlfriend, find out your language and hers, and learn how the two of you communicate and how to accommodate the other.  When my fiancee and I went through a similar struggle, we found this to help - turns out my language is acts of affection and physical touch (most guys IMO lol).  Hers are words of affirmation and quality time.  So we learned how we liked to be loved and to show love, this was one of the biggest keys for both of us as we were blind to each other's attempts to show affection.  Now that we have a better understanding of what our love "looks like" and how we like to communicate, all the small mediocre problems turn into something we both want to tackle to advance...it's no longer an argument and more of a challenge that we as a team (read relationship) get to solve.  It's been amazing to experience this shift in perspective.  

Sorry for the novel, I know I didn't directly address your concerns, but it seems like there some deeper bahviour that is contributing to your current struggle, so I hope in some way this was helpful.

Theres light at the end of the tunnel if you two want to walk together.  Take care of yourself, be kind, and stay healthy.

P.S. don't make decisions when you're angry, breathe, wait for the emotion to pass and come at the problem from a point of clarity.