I can only tell you what works for me in situations like this. I try to think of all the unfortunate people who have really, really serious illnesses and problems and then I can re-focus and give thanks that my problems are so minimal.
It happened to me once and it was my own fault. At least you couldn't help it.
I bought an eggplant parmesan. I ALWAYS read the labels, but since I had this brand before, I didn't see a need to. I accidently picked up BAKED eggplant parmesan and it had meat in it! I didn't realize it until I ate some. Of course, I threw it away after the 1st bite.