Pregnant—major weight loss

I’m 17+1 weeks pregnant. We tried for two ears after a miscarriage to create this baby and we’ve found out it’s a boy! I want to make sure he gets what he needs so I’ve been drinking nothing but water and juice and milk and eating as healthily as I can but I went from 240 lbs at 6 weeks to 185 lbs at 17 weeks. The doctors say the baby is growing accordingly but I just feel like somethings wrong and I want to gain some weight. All of my clothes are too big now! What should I eat to gain some healthy weight(not just fat)