Is AUTHOR wrong in the post ? POST : Throw away account because my co-workers know

I worked at big box  store thats was open 24hr and I've working b overnights   for a little over 3 years 

However as Monday (my last night was shift was Friday)  they switched me back to days and, because of that my sleep schedule was fucked. Fast forward to a few to Tuesday ago and I'm scheduled 10-6 , and I'm exhausted, so like any  tired worker, I come in with a thermos full of coffee. However.... The manager told me I can't bring coffee and since it's against store policy.  This is the first time I've heard this . Underal circumstances I'd understand. 

But 4 of coworkers had thermoses of coffee (all of them were on their phones)  , one of whom is known for her 48oz thing of coffee with her name embroidered on the mug.   and top of that I've seen the my relief  come in at 6 with hers and the manager didn't say anything to her. 

So I'm fairly grumpy but polite, and essentially say "it's been a big jump from doing nights to days, I'm exhausted" 

"her responses it's against store policy blah blah" she doesn't say anything else to the other people with coffee just me. 

This time her tone was incredibly rude and impatient 

 I gesture to be group saying what about them? She ignores the question and tells me to dump it out NOW. respond with

 "i quit, and you can forget about me having do nights"  I throw my badge away and walk to my car and sleep for the rest of the day.  I my friend called me the other day saying but unbeknownst to me my manager was really good friends with these people so that might had something to do with it.