The symptoms might be just part of your new lifestyle after your baby's birth. This is because you have mentioned your all known medical problems are under control. It is fine to take nap while baby is asleep. But check your hemoglobin
as it tends to go down when you are breastfeeding
baby. This is to rule out common cause of exaustion in breastfeeding moms. I hope you are also on iron and calcium supplements
along with vit D supplementation. Get your random sugar also checked and drink enough fluids and keep a schedule of eating appropriate calories. Do not remain without water or food for more than 3 hours. This should improve your energy levels. Let me know hemoglobin status. Take care.