Breastfeeding: How Come I Can't Quit You?

Dear Because I Said So, My daughter is almost 8 months old, and I've been struggling with the conflicting desires to breastfeed her forever and to never have to pump again. I dream about getting a full night's sleep, but each day I worry that I won't make enough milk for the next if I don't wake up to pump. And making the choice to continue breastfeeding means a (literal) drain on me all day at work. I get sad thinking my baby won't need me as much if I quit, and have this weird feeling...