My 3 month old has screamed for hours and will not sleep and it is just so unusual for him. I've given him calpol on the off chance but it hasn't helped, he doesn't have a temperature, I've changed his nappy, he's fed and fed but he just won't stop crying and he won't fall asleep. I'm worried somethings wrong because it is just not like him but I can't exactly turn up at A&E because a baby is crying. Can this just happen sometimes? What can I do? I'm getting overwhelmed now and I just don't know what's wrong with him 