weird feelings abt my bff (long)

So about a month ago, my friend told me she liked me romantically. Weve been friends for two years, and for a little while I liked her during our first year of friendship. Before she confessed, she talked about a crush on twitter, and I was jealous, because I thought she was talking about someone else. I wished she was talking about me. Turns out, she was! She confessed to me and I couldn't stop smiling. I was shaking, even. I told her I liked her too and we didnt make anything official, but we changed a little bit. We sent more pics of eachother and called eachother cute and stuff. Then a few days later I started feeling weird about it. I could no longer think of her romantically, and I suddenly felt emotionally unavailable. I told her and I felt absolutely horrible. We're still best friends, and we even have a camping trip planned soon. But yesterday we were talking about watching the sunset together and I suddenly wanted to kiss her. I couldnt stop thinking about holding her hand and kissing her and I'm so confused because I already rejected her. Why do I feel this way? Am I just craving affection? Or did I reject her only because I'm scared of having a relationship with her?