My (25M) gf (24F) wants to break up cause I didn't eat the last slice of pizza

So its Sunday literally nothing going on, and we made a frozen pizza. We both had two slices and that was it and we didn't finish the pizza. So there was one slice left and we where just sitting and it was 2 AM and I guess she decided to eat the slice, but she didn't eat it and set it on the coffee table next to the pizza box. So fast forward to the next day I go to grab the box to throw it away and I see the slice. I asked her why didn't you eat the last slice and she says "I was gonna but you didn't eat it so I just left it". I'm thinking to myself why would I eat it when I'm not hungry. So I asked why I would eat it and she says cause I was gonna eat it but you didn't and it's just sitting there on the table. So then I'm thinking why would she tell me to eat it when she was gonna eat it. So I asked her and she got mad and said take a walk. So I did and when I came back she was packing her bags and said she thinks we should go our separate ways. I don't understand why would this be a reason for her to end it. Its been 2 days now and we haven't texted at all and she hasn't answered any of my calls.<br><br>EDIT: This happened Sunday night and I think she wants to break up because she was gonna and she was gonna eat the pizza and I didn't eat it and it ruined her plan to break up with me.<br><br>EDIT: I didn't eat the pizza because I wasn't hungry and It was two days since we ate it and it was next to the box