Don’t wanna work there anymore ☹️

I am eighteen and he is...probably in his early twenties. I’ve been thinking about him lately, for weeks and it’s wrong. I wanna not believe that it is wrong because he is my manager. I’ve known him for almost a year and I’ve worked at my job for two years. Ever since last week he’s been treating me really bad and I am not sure why. I have no idea why he’s treating me like this. He’s been giving me really bad looks, slamming doors, throwing things, ignoring me, no longer greeting me with a smile. And I just feel like not enough. I know it’s not possible to be together but I at least wanna have a good coworker relationship. But if he’s gonna keep treating me bad, then I will quit my job and find another. I don’t handle shitty behavior from those that I treat good.