Mixed Signals.

Hi, I am having problems with this guy I like. He's mysterious and shy but then at times he can be a goof. He has tons of girls falling for him. First things first, a year ago. We were quite close, he would ask for me for advice when a girl asked him out and how to turn her down gently, he piggybacked me once in the last day of our school year, he teases me, etc. Though somehow, this year since we are no longer classmates only in 2 periods....He talks to me occasionally, teasing me when he saw my drawing in PE (having an assignment, he sits diagonal back of me) saying "Everyone drawing is better than mine, except for Nikki" He smiled at me as he said that. I handed my drawing to my guy friend who sits BEHIND me. My crushed asked "Oh let me see" He stopped drawing, just to look at mine. He let out a smile, as he poses like the drawing I made. He teased me (NOT meanly.) He stares at me constantly. One time, I asked him to see his report on the assignment we were doing. He filled through his folder and I saw a letter thing. He looked straight at me and said "It's nothing." As time passed, my EX-Best friend whom was his ex-crush who my EX-best friend liked back then as well. Sorta like a love triangle. Well, she got asked out and that's when things out of hand. He was standing next to me when that happened. He was talking to his best friend and they were laughing but I see him staring at her sometimes with a sad gloomy face on. Does he like her? Or have lingering feelings for her? They are seen talking occasionally now, flirting in front of my face. Such as tracks, they were cracking jokes to one another. I forgot to mention, I see him staring at a girl as well...though he could just be staring at her since I sit in front of her. As time progressed we barely talk due to his mysterious attitude towards me. He is seen staring at me as well, then looking down when I catch him. Such as me, looking behind for the time. He looked at me, and then looks down. Scribbling something down. Right now, he usually rolls his eyes when he sees me talking to other guys or even just hanging out with my guys friends, tapping their shoulder to lend me my binder (since my guy friend sits in my seat for an assignment). Example: I had an appointment to go to the doctor, so I couldn't go to Tracks (he's my teammate there) well...I asked my close guy friend John. To help me. We were laughing down the hallways, talking about stuff, then I see him. He walks out of the class and just stares at me. We lock eyes. Staring at one another for awhile. Then out of nowhere, he rolls his eyes at me. Walking away as if....I was nothing. I don't know what to think. He smiled at my childish behavior once, but then was he looked at me. He stopped smiling and looked away. My friends whom I ask advice for thinks he's trying to make me jealous and likes me. He gives me mix signals, so do you think he likes my Ex-Best Friend? Or does he like me? The other girl? Help? :|