I have never been really slim but during my 2nd pregnancy I gained 30 lbs. My baby weighted 10lbs, the other 20 lbs stayed with me. Over the years the I gained a little, lost a little, gained again. Then I was in a bad accident and had accident and had several surgeries, had to take about 10 different antibiotics over the course of a year and would end up with a completely out of balance intestinal system. An over whelming tired ness at all times and stomach pains, fogginess so bad that driving in a car became scary.