Struggling at work

A few weeks ago, I got yelled at by an employee that I wasn’t good at my job who the day before complained about my phone usage and I stood up for myself to my boss about it bc she uses the phone the same amount of time. I told my boss I can’t work with that employee anymore but was unable to move my shift and since then my enjoyment of work has diminished. I work at a library and we aren’t allowed to do anything at the desk but there’s constant social expectations, noises, and lights. Yesterday was my birthday and I got an email from my boss sent to the whole department that we are supposed to bring treats on our birthday but I didn’t work that day and just didn’t know it was a social expectation to do for the day before and just got really annoyed and mad. My boss makes me a to do list and today there were new ones she made in my folder and they had a whole paragraph on my phone usage and how if I don’t improve it, I have to put it on the back counter. I started crying when reading it bc it brought me back to being yelled at by my coworker but also there are other coworkers who use the phone as much as I am and I don’t understand why I’m the one who is being treated this way. Idk if anyone else has similar experiences or advice but anything helps. Thankfully I’m planning to move in a few months but I just struggling to get through until then.