For me, you have the power to choose to do one of two things:
[1] Decide to waste your time & energy on finding out who your competition is. (Which, after you know, it still doesn't make a real difference that I can see.)
[2] Choose to spend your time & energy more productively, thinking of ways to "win the girl", as it were. What are your good qualities that you want to show her? What's the best way for you to show her that any other choice (no matter who that may be) will not measure up to you, in the long run?
Note: You can only
show her by your words and actions. You can't "make her" see it. You just gotta work on YOU doing a good enough job of representing all your good stuff in ways that she absolutely, positively cannot miss

.
I don't know for sure, but it's possible that your friends are just having some fun at your expense -- it sounds like maybe you make it too easy for them to mess with your head (getting all wired over something that is causing you to waste your own time & energy, kind of thing.)