The fact that you feel lousy about the situation means you aren't a jerk. A jerk would just discard someone without regard for her feelings. Your mutual friends should understand that you can't just make yourself love someone that you don't feel chemistry with. They might feel uncomfortable being in the middle if you were to have a fight with this girl, but really, it's only been two weeks. So you've had sex? So what, you're two consenting adults and she couldn't have possibly imagined herself to be *really* in love with you on the first date. Or after two weeks if she really examines her feelings objectively.
