Not sure why but it's my sixth in less than a month. I get it really bad each time, lasting from 6 - 48 hours each time. I then recover and feel completely normal again, before getting hit by it again in a few days time. The cramps are excruciating each time and baby seems very bothered by it each time. This last one I'm having, the baby was already going crazy before I even realised that I was going to be ill and true enough 2 hours later cramps/vomit/diarrhoea started. Around 33 weeks pregnant now and really worried.