In the short term (a day or two) I don't mind feeding my cravings for weird things as long as I stay within my calories. A couple days of just eating cereal, even junky cereal, won't kill you and it may provide some sort of psychological thing you need (cereal is both easy and comforting and sometimes we need that!). If you are going to prolong your cereal vacation then I'd toss the junky ones (or limit them to one small serving a day) go for high nutrient & fiber, low sugar, and add fresh berries or other fruit. I used to use yogurt on my cereal rather than milk, then I progressed to more yogurt, less cereal, and now I seldom add any cereal at all to my yogurt (more likely to toss in a few almonds if I'm want some crunch.).
I doubt that a week form now you'll still be wanting to eat only cereal.
"Vision without action is a daydream ~ Action without vision is a nightmare"