My son is 17 months old. Every 2/3 weeks he is up at night squirming around and waking up every hour or so upset. The next day he won't eat and will be utterly miserable. He will eventually poo and it's the most disgusting thing I've ever smelt or seen. It's always a mixture of what looks like diarrhea and pebbly type poos mixed (sorry). Afterwards he will be ravenous and cheers up. I've tried writing down his foods and trying to find a correlation but I can't. Does this sound normal? Or am I missing something?