I'm afraid to tell my best friend that he is my best friend because I'm afraid he won't feel the same way
Why do you think he might not feel the same way about you?
I just get the feeling that he doesn't want to be best friends with me.
In a true friendship, it's good to be honest, and that includes being honest about your feelings. You never know how someone else feels unless you ask them, so you should share how you feel with them and see if they feel the same way about you.
I really don't want him to feel uncomfortable. I might wait it out.
I think it's okay either way. It's okay if you feel closer to him than he does to you. As long as you are happy with his friendship, it's not that important how you define it.