Friends are more than just the people you hang out with. They make you laugh, they keep your secrets, they offer advice (some good, some bad), they give you a shoulder to cry on. Sometimes they move away, or betray your trust, or flake out, but mostly they are the people who are always there for you. And they know you'll be there when they need you most. Because that's what it means to be a friend.
Sometimes friendship is overwhelming, sometimes it's confusing, sometimes you feel like you don't have a friend, but don't worry, it's like that for everyone.