🆘Smoking while breastfeeding

I'm currently bottle-feeding but do want to start breastfeeding my baby again.. I stopped bc or latching problems and ended up smoking again. I use weed to help me eat (I'm very UNDERWEIGHT and anemic) and for postpartum depression/anxiety.. I want to start breastfeeding again before I completely dry out but I also need to eat to be able to lactate.. will it be okay to smoke while breastfeeding and will it show in the baby's blood or urine?