I lost it

I cussed at a student or two regarding them asking for some of my canned tea that was on my desk that I still hadn’t had the option to put away this morning and I lost it. Was it genuinely about the student asking for the drink. Not entirely, but it was like the 10374639 time this semester that a student had asked for my food and drink. I am still grieving the loss of my grandfather and I hate that I wasn’t able to visit him in person before he passed. I literally came back to work sick but hey I have a voice which I didn’t have one on Friday. I’m so mentally, physically, and emotionally exhausted. I am at least going to get a formal write up… any advice on what to do would be helpful. Thank you!

Edit: Should have put not a teacher but I manage my own classroom with 40 kids in every period of the school day. I’m unfortunately an IA so a Union Rep won’t help me.