What should I do about having thoughts about my best friend?
Can you tell me more about this?
I can't tell if I'm his friend anymore because he always insults me
It's reasonable to have feelings for a friend after you've spent enough time around them. Have you thought about sitting down with them and talking to  them about how they treat you and what you feel about them?
I think I like my best friend omg
You really can't help who you have feelings for. However, you have to think about your relationship with your friend logically. Ask yourself if it is likely that your friend feels the same.