How to get over mixed up feelings.?

You need to understand that you two aren't going to be a couple in the foreseeable future. You're his best friend and he's yours. If he's making you mad let him know. If he needs a friend to help him, that's you... you're his best friend. If you no longer want to be best friend than that's fine. But you have to understand that he will rely on you and you should rely on him, that's what friends are for.