Maternal diabetic... can't stop eating help

Mom, I'm currently 7 months pregnant... the doctor said my weight is already excessive. I'm advised to diet and especially stop eating sweets. I don't know why, but I just can't... I can't give up my favorite ice cream and chocolate. My husband gets angry all the time; he says I don't care about our baby. It's not like that... it's just that if I don't eat something sweet, I feel dizzy and I keep craving it.