>>1 There are loads of kids like your who are by themselves and are probably thinking the same thing you are. Try approaching them, take a chance :)
Or try joining a club at your school, for example, it's a good way to make friends and get into a group of people.
As for your friend, just keep trying to ask him to hang out, but if he looks like he has no interest, there isn't much you can do. That's how friendships tend to be at that age.