Me and my girlfriend have been in a long-distance relationship for over 2 years. As of recent, we've had a really rough patch with plenty of arguments and spats, and it feels like nothing I can do will help us. I completely admit that I have done things wrong and I actively try to be there for her through rough times, and show her no judgment when she comes to me with her issues, the same way that she does for me.
The issue is that as of recent, she has become more and more disinterested/not engaged with me as a person. She rarely asks how I am anymore, which I have been able to excuse as she is going through a rough time, but a lot of the time recently I will say "I love you" and she'll reply and completely ignore that part of the message as if I didn't say anything, and won't respond with saying it back to me. She has also become quite nasty during our arguments which was an issue I struggled with a lot during the first year of our relationship (I get frustrated, don't handle my emotions properly, and snap) but I try my utmost now to be civil and calm during our arguments whereas she has shouted at me down the phone even after I've asked her to please be nicer to me.
I am willing to write off every single time she upsets me as a reaction to something I have done wrong or an accident when she is frustrated. I have brought these issues up to her, but there is no improvement and she is exactly the same in our next argument. I'm unsure of what to do. I love her more than anything in the world and would do anything for her, but it seems like no matter what I do anymore I either upset her or do something wrong. How can I go about things in a way that won't upset her, and will get her to be kinder to me again?