Slept with friend. still in friend zone? WTF

I had chased this girl for about 2 years to no avail, than we had a falling out and we didn't speak for about 3 years. Then she messages me out of the blue over facebook back in April. We start talking again and hanging out once in a while and this time I felt like I could just be her friend, I thought the feelings were gone. So 2 months go by and shes seeing a guy that she just kinda likes but this time it doesn't bother me. I went to Montana with my buddy looking for work and as soon as I was on the bus she started texting me about how much she already missed me. The entire 3 weeks I was in MT. we talked over the phone almost every night.... the feelings started coming back. I missed her too and I hadn't found any work and was running out of money. So I hopped on a bus and went back home. 3000 mile later I call her and surprise her by letting her know i'm back in Florida and she'll be able to see me tomorrow. she was thrilled. The very night I get back in town I go to see her. we spend the entire night together just hangin out, driving around town, just shootin the shit. So around 4 A.M. we're back in her driveway sitting in my car. The conversation gets on the subject of sex... and yada,yada,yada you get the point. Right after we get done she looks at me and tells me not to fall in love with her. I promise her that i'll always be her friend and tell her that she knows I already love her, which she acknowledges. less than a week later she goes to the birthday party of one of her ex-boyfriends and hooks back up with him. now they are officially a couple and they seem happy together. She tells me that she can't be with me because I'm too innocent according to her. She's only the second woman I've slept with and she knows it. I really don't know what to do. I'm happy for her, but it hurts a little. And I can't just stop being her friend. The idea of doing that again hurts more.