Is he teething ?
Olly went through a week of this last month, his back molars were making an appearance.
We have a teething anklet that he wears all the time and the only signs were his cheeks were red, refused all food (had to revert back to mush) and nasty nappies and sore bum.
I keep a few of those Heinz fruit pouches and the desert pots in the fridge for him, its all he will eat when he is like this
xx