I don't understand why my housemate next year has issues with me?

I'll be finishing uni in a months time but because I've made lots friends in the lower years I've decided to stay in the town as I'm not from there. Everyone will be staying in university halls and want to be included in the parties and the student events

What I decided to do is find a flat share, I'll be sharing with 3 other students 2 girls and a guy, my rent payment would be a normal and won't be effecting their student payments.

I don't know them, I applied through a advertisement one of them put up who was the head tenant, I added her on facebook and chatted with her. I saw her in a club few weeks ago and she came up with her housemates and introduced them to me, the other girl was really nice but the guy didn't seem phased, he hardly said anything to me.

2nd time I saw the guy again another night, I was out with a group of girl-friends and went up and said hello, I was drunk everyone else just having a laugh but he just walked away without saying much.

3rd time I saw him in the smoking area at a club, I could see he was on his own so went up to him saying he could join my group of friends until he finds his own but he said no to me and just stood there on his own, told me to leave him alone.

I've seen the two girls to and they would chat to see, only briefly because both with different groups. Mainly talked about moving in and just general things what I'm doing that night.

I don't know if the guy has a issue with me moving in, maybe its because I'm another man and I'll have friends friends coming over too, I don't know he just doesn't want to know me but I just see being rude not making a effort with people you'll be living with.

What can I do when I see him? I haven't even had a chance to get to know him. so how can I? but I don't want it to be too forced.

Are you gay?