Confused about feelings for friend

Firstly I would like to provide some background. I am a 19yo female and have only ever had 1 boyfriend. We broke up a year ago but are still very close friends. This year I met a girl and we get along great. She and him are the two people closest to me in my life. About a month ago my female friend came over to keep me company while my parents were away for the weekend. We had a bit too much wine during the evening. She told me that she loved me(as a friend) and then she kissed me. We made out for a while but were too drunk to really do anything else and just went to sleep. The next morning we both just carried on as usual until she went home. I told my male friend about it because it was really bothering me and I felt very confused. I had never really entertained the thought of being with girls before. I couldn't stop thinking about her. The problem is that she has a boyfriend and they've been together for almost 8 months now. I feel guilty, confused and sad whenever I think about it. A few weeks later I talked to her about it telling her how confused I felt. She told me that she was very sorry about what happened. She mentioned that she had considered herself a lesbian up until last year and had kissed another girl before. She told me that it still bothers her what happened between us and that she didn't want to lose my friendship. She has not told her boyfriend about it. I also know that her boyfriend isn't fond of me because of the closeness we share. He complains to her that he feels left out. She also said that if her boyfriend didn't exist she would date me. Now I don't know what to feel anymore. I find her attractive and enjoy hanging out with her. I would do anything for her. A simple touch from her makes my heart beat faster sometimes. My other friend thinks I'm in love with her but I don't know. I could simply be lonely. Please any advice on what I should do about the situation? Any thoughts or suggestions are appreciated.