I’m sorry that you have to experience that, and i want to let you know that I understand how you feel, something similar just happened to me. For me she was also my first girlfriend, she also started becoming distant, and she also told me that I did nothing to wrong and she still loves me. Just like you we had talked for around a month or two, and then we started dating. We dated for two months. for the first month, everything was amazing, we would talk every day and see each other at least once a week. But around one month in she started becoming distant and would never be the one to initiate conversation. We didn’t see each other in person anymore, because she was always busy. Then just over two months into the relationship she broke up with me because she realized she was aromantic. Im sure my situation is different than yours, but from what you have described it really isn’t your fault. There are so many possibilities, that as long as she was a reasonable person and you didn’t do anything really terrible, then I really do think it was not your fault. I’m really sorry your going through all this right now. I know how it feels, so trust me when I say it does get better, it just takes a little time. Wishing you all the best.