Hi.i am new to this. im 12 weeks pregnant (this is my thirteenth week). i weigh 100 pounds and my bmi is 18.5. my doctor told me that i have to gain weight by this month. but due to nausea and frequent vomit i actually lost 2 kgs! very worried, i also lost somewhat the belly i had begin to grow. is this really bad for the baby?? :'(