Should I pay her back?

I was in a relationship with a girl and we moved in together. Before that, she paid for a ticket that I had gotten but never paid, I paid her back for that. Then, while we were living together, my license was suspended and I couldn't drive to work, she drove me to work and back and also took time off work to do this. Then we broke up and walked out on the lease of the apt that we had. They charged us 1800 for this and it went on our credit record. I moved into my parents house and she moved out to AZ where she tried to get an apt. With the money we owed on our old apt on our credit she wasn't able to get an apt till she paid it. so she did and i paid her back my half for that. Now she wants me to pay her back $2000 for what she did for me while we were living together. She says if I don't pay her back, she will sue me. What my question is, is if I don't pay her back, can she sue me and win? I don't think she has much proof of what she did for me so i don't think she has much ground to stand on.