I think he likes me but he's confusing me? (guys please help, and girls too. =))?

So I'm a junior in highschool and there's this guy who is driving me crazy. We always look at eachother. Every time I walk into the place where we both have lunch he always notices me.(I see him look at me from peripheral vision) My friends have told me he looks at me as well. So, our lunch period is basically the only time when we see each other. (he's a senior) Recently, we've become full-time partners at a sport. At first when we played together, he seemed extremely nervous and nice but more recently I've gotten a slight sense that he may not like me as much as I thought? I've been told that if a guy likes you he'll try to make conversation with you no matter what. There was a time when he hit me with a birdie on the head during the game but he didn't say sorry. Like we all laughed at the situation but I was sort of surprised he didn't say sorry. (I thought guys we extra nice to girls they liked) All he did was smile "sheepishly"? (I try telling myself that it's because he's not the extremely romantic type because he plays it cool with all girls...including his ex girlfriend...to whom we played against.) When he smashed the birdie at his ex he didn't say sorry either. He just smiled in a friendly way. I'm really confused and I've tried numerous times to forget about him but his one smile he gave me just melted my heart completely. I would appreciate other people's opinions. =)