Guilt, Sad or Joyful?

For the past few days, I've been in a dilemma with these 3 emotions as stated on the title. Reason why I felt that way becuase of this particular girl that I went out with. Had a pleasant dinner on fri, and we were chatting and taking a stroll in town. We held hands together and didn't bother about the surroundings around us. The feeling was great, and I will never forget that. But, currently, she already has a bf. I know I shouldn't be doing this, but I cant help it. And she didn't mind too. And, when i asked her about her relationship with her bf, she said there's no chemistry, but still hanging on. She even said, if they were to break up, she would want me to be her bf. Was she joking or was she being serious? Was she hinting to me something? I really really have no clue. The past few nights, these thoughts were running through my mind. Sometimes I feel I shouldn't have known her at all. I really hope everything will turn out right for the upcoming says ahead. I agree with this song lyrics, "I pray for the stars to go on shining, cause in my dreams you will love me." by REO Speedwagon.