Wierd relationship, weve been through a lot but I really need help

ok I recently started dating a girl last year and are relationship was on and off for a while because we were having trust problems, like if I were to tell her a pretty big lie she would think everything I said is a lie too.. but we worked that out and got over it and starting dating again.. but then after a while a new problem came up I wasnt paying enough attention to her and and she thought I didnt really like her anymore, and she had some other guy on the table, But once again we worked it out and continued goin out together after I really did express my feelings to her and we fell for each other again. But then summer hit us and we didnt see each other as much except the occasional movie.

But heres the problem. I went on a vacation for only 3 days and when I came back I got a email sayin “we dont talk enough and this probly is better we didnt date anymore”. My original thought was “ok, we will get over this too, no big deal”. But once I started talking to her about it I found out that she found another guy which I guess “is a better guy” better looking, nicer. And I asked her how can get over me and move on to a new guy in THREE DAYS??!! so im pissed off then about that and now she says “she doesn’t feel the same way about me”. But I did get it out of her before that she still does love me and doesnt know how to break it off witht this other guy. But now she denies all that.. Help please I really know deep down she still loves me. And I really love this person and I wouldnt ever be able to get over her.