TIFU and shoved a customer

I had a relatively slow day at the pizzaria until 1pm when all hell broke loose. It was just me, I got my manager shirt Friday, and a driver. I received eight orders within two minutes of each other and ran out of mushrooms on top of it. After trying to call the customers to see if they would like a substitution, I was getting more behind by the minute. The guests were frustrated but understanding until this 50 year old Karen stopped in to pick up her order. She was with her teenage daughter and asked where her pizza was. I informed her what the situation was and that I hadn't started her food yet, and received nothing but attitude. She berated me, told me I wasn't working fast enough and anyone else could do a better job. I will admit, I lost it after a few minutes, yelled, and told her I would get to it as soon as I can and that I really was doing the best I could. She left but I saw her sitting out in her car. I felt bad and decided to skip to her meal to get her out as fast as possible. I call my driver, to find out that she is, of course, stuck in the snow, so I have no backup. I call the gm and let him know whats going on, pull myself together and keep going. I'm on the phone with another customer explaining the mushroom situation when I hear "are you fucking kidding me". Of course it's the woman from earlier. Of course her pizza was supposed to have shrooms... I tell her I'll be right with her, and she comes across the desk, and hangs the phone up on my call. I was incredulous and will admit, I asked what the fuck she was doing hanging up my phone on a customer. "I'm a customer" is her response. I told her not anymore, she needs to leave. My boss told me I could refuse service, she needs to go. Of course she threatens to call corporate, so I give her the gm's cell number and tell her he is on his way there if she wants to wait for him. She starts yelling that she just wants her pizza, I say, no, just leave, you haven't paid for it yet and I am not serving you. She starts waiving her card at me trying to pay, I keep saying no, so she comes around the counter saying she is going to get her pizza while I am yelling at her to go. She opens one food warmer, doesn't find it. She then walks further into the kitchen, toward the oven and me. I lost it. I freaked out. I shoved her back. That must have been her final straw because she starts screaming that she isn't just calling corporate, she's calling the cops, while shoving me and putting her fist in the air like she was going to punch me. I start crying and begging her to just leave, which she finally does while she is on the phone with the police. I knew I was going to jail for assault, and I tried to prepare myself for it in the back while I waited for the officer. In the end, the officer said we would just let it go, tempers flared, no one was hurt, and I didn't go to jail. We canceled her order, my boss helped me finish my orders and apologized to the rest of the customers. TL;DR: I got into an altercation a customer because she was hangry. She came behind the counter, I shoved her and the police were called.