Do facebook trackers exist?

[baby g]

I have a crush on this guy. I wanted to see if he was on facebook and found his profile. It's private only for friends and found my other friend was my crush's facebook friend. Well, noisy me when on her facebook to see when she added him as a friend. I ended up looking through her friend's list. Is their a way that she can tell if I was looking on her fb profile or ify crush can see if I was looking him up on facebook. At school, the two of them were acting mean to me like they knew I was looking on their fb. Is it just me or do they know that I was looking through their facebook page?
Mean as in when I ask my crush a question he would reply in a tone where he would rather not be talking to me. My friend would be demeaning and say stuff like " so what" it's no big deal and make me feel embarrassed and belittled.

[Dora]

They never know about it. Facebook doesn't provide such options to the users