Shy guys : i need your help!

Alright so i have class with this guy.. And he used to stare at me and id catch him looking at me, he'd even smile.. He tried sitting next to me but i told him that the seat was taken.. ( only because i didn't want him staring at me ) but he still sat close to me. He also sat next to me again before w/o saying a word.. Anyways one day he was behind me and asked what if he hit me with a book which was by my butt.. We then started talking but he seemed standoffish or nervous i think kinda like he didnt wanna talk . Anyways when i see him in the halls he acts all insecure or if hes ahead of me he'll walk slower but i end up walking ahead of him because i don't want it to be awkward. Couple days ago i was with a friend and he said whats up really quiet. I didnt see it but my friend did.. Today we were smiling at each other and he kept looking back at me a few times in class.. in the hallways he tries avoiding eye contact . he'll turn his head when I'm near obviously as if i cant see him. One day i was standing somewhere and i looked over and he was standing by the elevator and i seen him and went to the bathroom for a sec, i came out and he was still there. I walked away and looked back then i seen him walk off.. What does this mean?