I hate my bestfriend

So basically i have this best friends since the first year of high school (hes still my classmate). He annoyed me sometimes which i think is normal bc i see him basically every day. But over the summer break I've started to hate him i can't even bare to look at him. He copies almost everything i do. He doesnt have his own personality. I hate him and idk what to do about it i cant just drop him cus we have all the same classes and we sit together in almost everyone of them. And like today i didnt say hi to him so he just skipped the rest of the day cus he had a panick attack about it what should i do.