Is anyone intensely working out to extreme and Breastfeeding?Im trying to decide if i want to try to…

Is anyone intensely working out to extreme and Breastfeeding?Im trying to decide if i want to try to breastfeed again..i know ill be doing insanity and spin after i have baby..if you do..hows milk supply and are you losing weight faster then previous pregnancies.This is my 3 pregnancy i firmula fed due to problems i had but lost all weight in 5 months...Please tell me your experiences good and bad and if and what effected it.