Taking others food by mistake

So at work today they order food and I took the wrong plate.

I order lasagna and another other what I think is egg plant. And they look just the same so I took it and when I sat down to eat I saw seed so I was no this is not mine so I stoped eating and seance I had preach put the fork in I was like I will just take it and pay the lady for it. (I don’t like it) so when I try to explain it to the lady she just turn her back to me and wouldn’t answer me. I said sorry I thought that was mine but I just but the fork in it. Well know I’m here trying to stop crying because I feel bad and stupid. And to the fact that I’m just an inter here I feel like my last days are going to be hell.