<human>: Could you distill the essence of the text into 1-3 sentences?

I'm definitely quitting, but I'm wondering if I can do anything about this.

I've worked at a pizza place for two years. 
Some events:
Two guys intentionally used the "N" word to harass a girl with black siblings. Only one written up I believe.
A guy yelled "Fuck this!!" with a room full of customers and ditched work. I wrote him up since I was in charge but I don't think it went through. 
Another guy had threatened me and called me a bitch at work, (we used to be friends but a lot of bad things happened) he just had a talk with an owner. 

On Halloween I worked my ass off for five hours straight and as soon as it died down I sat down for a minute and was ridiculed. 
A new lady who runs the store for the owner acts nice to my face but tries to get people to work all my shifts because I'm a bad closing supervisor, but until two weeks ago I hadn't of closed since December. She's been there since May. 
She told the owners to meet with me and talk last Saturday but didn't inform me, so when I obviously didn't show up one of the owners crossed out my shifts and I now can only work once a week. 

When I talked to an owner he told me that "I've caused trouble recently" and mentioned when I reporting that coworker for calling me names and threatening me.

Coworkers say I've always had unfair treatment. 
I'm the only homosexual at my work place.
<bot>: My work place is always on my case and I'm the only person who gets punished for anything and I'm homosexual. What can I do?