Long Distance Relationship with ADHD Girlfriend

Hello, I am a male, 26 years old non ADHD . Currently i'm in a long distance relationship with my girlfriend . She is 26 years old with ADHD . I will tell the story about my GF first . She has lived alone for 7 years because her parents works overseas and never come back in the past few years . She doesn't have many friends . Her only close friend is a girl, 30 years old with ADHD too, currently not married and never been in a relationship with anybody . We have been in relationship for almost 7 months . at first, everything goes okay and not so many problems with communication even though we live in different city . She even make me a handmade scrapbook when i came to visit her . We talk about what will our family will be, we talk about the future, we talk about moving into the same city . At 2 months of our relationship, she told me that she have ADHD . At first, I don't know anything about it and i thought that it was not a big problem for us . But everything change until my GF wants a breakup . She told me "I lost feeling with this relationship, and i don't think you could handle with me in marriage . I love my single life and i don't even know what happen with me" . "I lost feeling with you and don't think to get into any relationship with the other guy, i will just make your dream and other guy dream ruined" What happen with her ? Is ADHD can make a mood swing that fast ? What should i do with her ? I love her but i don't even know how to do right now . In my case, does her ADHD friend makes situation better or worse ?