Faking my pregnancy

I’m currently pregnant for the second time, the first ended in a miscarriage. I was already plus-size before my pregnancy, so I’m not showing as much as your average woman. I’m into my 6th month and finally feeling at ease about this pregnancy. My husband and I were with his mother yesterday and she proceeded to tell us that his sister and nephew (who’s older than my husband) don’t think that I’m pregnant because my stomach isn’t “big enough.” My husband is such a calm and non confrontational person, so I know he won’t say anything to them, but I’m so hurt, angry, and upset. Just needed to vent.