Hey Personality,
Considering I can't speak any other languages you are doing a great job of writing English, though it is hard to follow. I am concerned by both your writing style, and in particular the things you say that perhaps you are still in high school, and are quite young.
Reading between the lines this is what I understand:
1) Your friend's girlfriend introduced you to a girl
2) You meet up again, but you don't say where.
3) You go straight back to your place, but you live with your parents, and that creeped her out.
4) You only are talking about meeting up and going to your bed.. where is any kind of interaction, connection.. anything?
5) You fooled around sexually, and the next day she was flaky and cold towards you.
6) You think that your best friend's girlfriend likes you and because of this you think he said something bad about you to the girl. Your friend and his girlfriend since broke up, and his ex-gf now flirts with you. for this reason you think perhaps she has said bad things about you to the girl. NOW THIS REALLY SEEMS LIKE HIGH SChOOL IMMATURITY!
7) I think that you said she currently has a boyfriend that she didn't tell you about, but that is difficult to tell from your English.
Giving you the benefit of the doubt here, as I promised you an answer in email.
Two things spring to mind. The first has nothing to do with any influence form your friend's ex-gf. The girl you like was into you sexually, and then went cold and flaky towards you. Without knowing more details.. this seems like "Buyer's Remorse." that means that she was into you at the time, and is actually attracted to you (in your described case,) but there was never any real connection between the two of you. Only a rush towards sexual gratification.
Therefore, you missed out Comfort! You missed out actually getting to know each other. Upon leaving you she reflected on this, and realised that she didn't feel good about it. Due to the fast sexual escalation she also possibly feels like you are now Expecting sex almost immediately upon seeing her again. She possibly feels like that if she does get to be alone with you again then sex is inevitable because she would be turned on also.
BUT.. she doesn't feel comfortable with that, because she doesn't really know you on a deeper level. There was no real comfort and connection between the two of you. So the anticipation of getting all hot and heavy with such a superficial basis is giving her anxiety about seeing you again.
Put another way, she doesn't think you have any sincere feelings for her, as all you are interested in is sex.
Any negative comments planted by a friend would add to her concerns.
If she has a current boyfriend then she may really like you but feels guilty.
It could be a combination of these things. From what you wrote though it does seem that she actually likes you. I would recommend speaking with her, and dissipating any concerns by stating the obvious.. something like "look I know we got carried away the other night, and you really turn me on.. but I barely know you, so let's just meet and hang out as friends and actually get to know each other.. I promise I'll behave myself if you can control yourself."
Then of course if you get to see her again. Still flirt, etc.. but actually get to know each other so that there is sexual attraction + feelings of comfort, trust, and protection between you. Then if you choose you can state your concerns about things that may have or may not have been said to her. Keep it brief though, be sincere, and be confident. Effectively calling out the elephant in the room.
Good luck.
P.S.
If you do happen to be under 18 then please respect the people on this board, and read, rather than asking questions. Getting older, and developing emotional maturity will resolve many of the problems that younger guys face. Such problems lose relevancy for older board members. I can revisit my stance on the age restriction of the board, and will speak with my attorney about adding an "Under 21" or "Under 18" Topic Category if enough people request it. My other concern about younger guys is that they too easily lose sight of what is truly important. They get into "game" and that changes their attitudes to life in general, where they become ego driven, win/lose oriented, and lose respect for women and ultimately themselves also. In addition to all the good that has come from this current men's movement, there is a dark side. I think there is potentially a lot of damage being done by the "seduction community" by how it has influenced the thoughts of emotionally immature men.
