how do i get my girl back

me and ex were rough 24/7. it was only a month and a half of dating but i fell inlove. well i fell inlove to late. before we dated i had jsut got out of a relationship that wasnt serious at all. and it hasn’t even been a week before i started dating again. i started loving her to my fullest when it was to late and she was ready to leave. she said she still loved me a lot and she wanted us to workout, but her mental is bad and she’s tired of getting hurt. i hurt her bad but im changing and im ready to love this girl with all of my heart. do i let her go or should i fight for who i love, and what do i do