Should I be friends with this girl after what she did to me?

So I have been talking to this girl for about a month, we were talking every night for like 3-5 hrs, I asked her out and she said yes, then she canceled the date the next day, I worked out with her a few times.. I kept asking her out on a date she kept saying I'm busy, idk my plans.. I asked her out again last sat she said she didnt know her plans!! I finally told her I liked her.. she replied with. " Thats very sweet of you. But I'm dating someone right now, you're a great guy, and we can totally get to know each other better!! I replied with " I totally understand :) hope this did not make things awkward between us! I would still like to become friends with u.. I feel like **** right now. My question is should I be friends with her or now?? I txt her since sat.. I saw her at the gym tonight and when I walked in she went over to her boyfriend and kissed him, in front of me.. I think she is kind of a B****.. But tonight I hung out with her and some friends, my buddy and his girl and me and her,, awkward.. Well my buddy left with his girl, the plan was I could sit and talk to her, but she left as soon as they did, I payed for her.. She gave me a hug goodbye, and then she wanted to street race me home!! lol I killed her but I kept slowing down and swerving.. I had her laughing really hard!! IDK what to do, I have feelings for her, but she does not feel the same way..