why was he so awkward?

Ok so my mom , aunt, cousin, and I rode the train to the american airline center to see an event. The dress code was upscale casual so I a floral dress and a short sleeve cardigan and flats doing my hair and makeup more dressy than usual. On our way back we had to make like 7 stops and switch a train so when we finally exited and were walking to the parking lot to get our car I saw some kids get off using another door farther down and thought to myself 'those look like people (let's call him sam) would hangout with'... sure enough I see him get off last and I'm thinking crap I hope he doesn't recognize me, its hot and I'm probably sweating and the train ride was packed and long. So the train leaves and we cross the track to go to the parking lot and him and his friends are standing there like its cool to hang out in the hot heat at the train station. They were really just being loud and playing music and stuff, which I wouldn't have minded but I was with my mom. We had to pass them to get on the crosswalk and I acted like I was looking at my phone even though it had died at the event. While I was passing I accidently made eye contact with on of his friends he looked up saw me and he was screaming 'hey,hey' and I acted like I didn't see him and he wasn't talking to me and we walked pass them but we were only a couple yards away and we had to stand there until we could cross the street. All of a suddden BAM! there he is standing behind me almost making me jump! He said hey and I said hey I was really thinkin oh my gosh I don't feel seein anyone from school'. Then he tried to give me a hug which was awkward because I don't even talk to him like were friends at school only the rare occasions that he's actually in class and the only coversation I recall him having with me was the one where he asked for my number and I said no! So I don't see why he was trying to hug me outside of school. Then he was still standing there and he's like so your with your family and I'm thinking d these 2 women look like my friends?! But I just say yep... then he's like which one is your mom I point to her and he's like I can see the resemblance! At that point I don't know what to say so I just smile wondering why that street has to be so busy. Then he turns to my cousin whose listening to her ipod and he's says is this your sister? And I say cousin and she's just standing there an I'm wondering why she isn't trying to save me! Then he's like oh your cousin?! I've seen her before. And I say well she went to our school and he's like no that's not it and I say she just graduated (I saw him at the graduation too) he's like nope , I'm thinking well then you didn't see her and if you did then it must've been at target or something. But then my mom saves us and says we can cross the street! We get to the car and my mom and aunt are like whose that and I'm like just a guy frm class and my cousin says that she saw someone she knew but didn't go and say hi. Now looking back that was the awkwardest conversation ever! What I'm really thinking is why didn't he go back over with his friends? I really feel bad now abou how rude I was and how I must've looked really mean cause he is kinda funny and stuff and has a outgoing personality but A why would he think it was okay to hug me when you can't even probably remember my name( he was like hey, hey) and B why are you acting like you wanna meet my whole family!

I'll probably talk to him when school starts but now I think its funny! tell me what you think of the situation