Postpartum Weight concerns...

Sooo I wasn't excalty petite when i first got pregnant, but i was losing weight. I would never have an appetite. I pretty much lived off of protein shakes/ meal replacements.. Would it be a problem if I just drinked protrein shakes/ meal replacements, ate some yogurt and take me prenatal vitamins to lose the baby weight faster? Is it okay to do while you're breastfeeding ? Would it harm the baby? And please no rude comments or sarcasm. I'm not in the mood to curse somebody out tonight.. Thanks ladies. Much love.