I have quite a confusing problem at the moment.

I really enjoy being best mates with this other male, and we are clsoe and can have such a good time and laugh together.

However, he has a tendency to get that little bit too close to me. He confuses me because I'm confused myself at this point in my life. I thought none of my other friends noticed that we got close to each other, until my other best friend who is also best friends with this guy confronted me about it today.

I became quite flustered and didn't know what to say so I just changed the conversation.

I was at a party with both of them and I had been drinking, which kind of made us two just get closer. At some points, I just felt it was too close. But I think I was comfortable with it.

I have no idea if he is bisexual, or if I'm bisexual for that matter, but I just need advice on what to do.

What is your definition of "close?"
If it makes you uncomfortable, tell him (respectfully) to back off. If you're comfortable with it, I would be cautious, and not get "involved" in a "close" way with people until your life is more stabilized and you aren't so confused about yourself. It's very difficult anyway for you to get involved with anyone until you know yourself and where you are going. If this is a confusing time for you, take a step back and learn more about yourself instead of worrying about everyone else.

I totally agree with jaime90. Well said ;)