U have to watch ur diet and incorporate workout into ur lifestyle. If u are breastfeeding, u may want to aim for about 1800 cal/day minimum and focus on proteins so that you can have proteins for the milk u are producing. Do some light cardio, u can consider joining or finding mums like urself to workout together. U can also take exercise time as ur "me-time". But before u start any exercise, u Shld check with ur Doctor if u are cleared. Stay hydrated and watch your heart rate