my husband and both of my children have celiac disease.
my husband was not diagnosed until after our daughter. But before he was diagnosed he always felt tired. He got sick with colds often. If he took me out on a date there was literally times that we would not make it home in time because everything would go straight through him in a matter of 30 minutes. He would go to the bathroom 5-10 times a day.
our daughter was the opposite. from the time she started solid foods and was off of breast milk she would get EXTREMELY constipated. so the point where she was in the ER getting barium tests and on a daily laxative and had hemorrhoids. she was also very thin, very pale, with very large dark bags under her eyes. She spent almost a year of her life vomiting every night. projectile sulfur smelling vomit and often had sulfur smelling burps.
We found out my daughter had it first, totally on accident (long story). but within 2 months of being on a gluten free diet she grew 2 inches and gained 7 lbs. she has been gluten free for 2 years now and is in the 90th percentile for height, 50th for weight, and is very bright. She looks a million times better too. When she went gluten free i made the whole family and my husband's stomach issues all went away. There have been a handful of times that they have gotten gluten and my husband has water stools and my daughter has violent vomiting to the point her eyes hemorrhage.
Our son has been on a gluten free diet since birth. with his dad, grandpa, sister and some cousin all having celiac disease (it is common in irish genes) he had a 70% likelihood. we didnt want him to go through the things our daughter did, so we started him gluten free. he has gotten into gluten a few times and when he does he gets extremely bad stomach cramps, gas, and then a very loose stooled diaper. definitely not fun for anyone.