I don't think you over-reacted at all! I honestly don't know how you manage to juggle four young children so don't beat yourself up, give yourself a medal instead. I'd be setting a rule - one chance to say what you want for breakfast, if you don't eat it, no alternatives so go hungry. That's not harsh - it's teaching responsibility for making choices.

And I'd be making him get the bus to school on set days. Honestly, packing four kids into the car for a five minute journey sounds like an horrendous start to the day when there IS a more relaxed alternative.

Don't feel bad.