I have often wondered if "Colic", the term they use for non-stop crying, isn't something that occurs in newly vaccinated babies.
I once helped a friend babysit an infant and the baby cried the entire 3 hours we had her. Nothing we did helped to comfort the baby. At the time it really disturbed me. I knew something was wrong with the child but didn't know what. The mother claimed she just had "colic" and said it is normal in a lot of babies.