not allowed to eat crab while pregnant

Hey moms, I'm feeling really sad right now. For the past two weeks, I've been craving crab, but my mother-in-law won't let me eat even a little bit. My husband always follows her lead, so he's constantly watching over me... I love crab, and I've been avoiding it since I got pregnant. But for some reason, I've been craving it so much in the past two weeks!!! I've been crying a lot and feeling stressed... sometimes I even feel small contractions in my belly. My mother-in-law says that if I eat crab, my child will become hyperactive... Is that true, moms?