Hah, Trailmix, I didn't know there was an acronym for that already, but I love it. I think my therapist just referred to it as mindfulness. She used to have me wear a rubber band on my wrist for a short while, and when I caught myself having those hurtful thoughts, I'd "snap" myself out of it.
It was a silly as it sounds, but the idea is to get into the habit of stopping when you have those thoughts, and instead thinking about why you're having them. Instead of calling myself an idiot, I stop and think about why I'm doing that. Am I just embarrassed? Did things just not turn out how I wanted? Do I know something now that I didn't know then, and that's what makes me "look stupid"? Etc.
There's always stuff acting on you all the time. When you have physical needs pressuring you on top of what's going on emotionally, it makes having clear thoughts much harder. You've gotta be fair to yourself. Taking a break from what's troubling you to take care of yourself is often enough to give you better perspective, or at the very least settle the rumblings from your tummy.