Forgive me, but the phrase "it's all in your head" tends to piss me off. Yes, sweetheart, it is all in your head, but only because that's where our brains, minds, and emotion controlling doo-hickeys are located (in theory, of course). The fact/theory that mental illinesses are rooted in the brain doesn't make the things we go through any less real and it certainly doesn't mean that we are making it all up. It's unfair that people dismiss you/us and your/our emotions so easily. I'm not saying that your reactions were proportionate, since I don't know what your reactions were, but I feel confident saying that simply having a reaction to someone dismissing you in that way is quite understandable to me.

Ahem, sorry for the rant, I also have disproportionate responses to stimuli.

My mother, who was diagnosed Bipolar when I was 6, tells me that when you feel like a failure try to tell yourself that you only failed at that moment in time. Maybe you did fail this morning, but that doesn't mean that you will fail tomorrow, or even for the rest of the day. However, it doesn't sound like you've failed to me. If the kids are still breathing, then you've won!