Kart Racing Catch

Ok, well i like this guy and he just moved next door to me. I have been hangong out with him for awhile. He knows I like him and for awhile it seemed like he liked me too. But now I'm not sure. Me and my friend went go kart racing with him and his cousins. When we got there, there was a group of really hott guys and me and my friend kept looking over and they would look back and smile. Well later, this other girl who I really don't like walked in, and she was flirting with him. She would check him out be all giggly and everything. And then it seemed like he was flirting with her because when I looked over he was tickling her like he does to me. He didn't really talk to me much the rest of the night. Sometimes we would catch eachothers stares and just look for a second or smile but nothing really more than that. I think I might have screwed up by flirting with those other guys. Now I feel really bad about it. I don't really get to see him a lot. How do I fix this?