I feel someone watching me sometimes and I turn around to see who it could be and it's always this one guy. And whenever I turn around to talk to my friends, out of the corner of my eye I can see him looking at me. Does this mean anything? Or is it just my mind playing games with me?
Well you could be imagining things if you like him. if he's actually looking at you he could like you, or maybe he thinks you weird looking, or he thinks your hot, maybe you have something on your shirt, maybe he's wondering about you, maybe he's wishing you would die. There's more options but I'll stop now.
He probably likes you. Guys don't seem to notice how much they stare at a lady when they like them.
if could mean he finds you attractive or it could mean he's looking at you because you're looking at him. I know you said that he looks at you, but maybe he thinks you're looking at him. and people are curious about those who stare at them