The worst morning sickness EVER!?

ok so my doctor just keeps telling me that "it normal it all normal" well ive had 2 kids before and never have i been this sick. so first question is could it be a boy? as both of my kids are girls? could there be more then one making me extra sick? i've spent the last 3 days eatting nothing but crackers and drinking ginger ale and its leaving me with no energy and sick on the couch all day. walking make me ill bending over to pick up after my kids makes me puke. so i guess the question is can't anyone tell me why i'm this sick and also what other then ginger ale and saltines will help with it? thanks so much i'll be watching for answers as life has been miserable the past couple days and i'm only 4 weeks preg.