Adult Coeliac: my tummy now swells when I go off my diet?

I am an adult coeliac and was diagnosed when I was an infant - 30 odd years ago. I have no health issues and have been very healthy (no symtoms since diagnosis) most of my life. I mainly stick to my diet and binge the very odd time but there are times that I eat a little bit of gluten occasionally and sometimes unknowingly. Up to now this has not bothered me or presented any symtoms. I have two children and since I had my youngest, she's 2 years old I have begun to show signs again of eating gluten. My question is ... is it normal for your tummy to swell (similiar to 6 or more months pregnant) when otherwise very well coeliacs eat gluten. Its so weird as this has not really happened to me in the past. I've always had a potbelly but what I get now is ridiculous. I am not underweight - I've always been a european size 12 but with my big belly I can now be a size 16 on certain days. I went for a scan of my kidneys, ovarys, pelvis bec of this bloating but could it be coeliac??