The author and her family spend Mother's Day at her son William's grave. Courtesy of Susie Shaw My early Mother's Days were joyful, then became a rare break from parenting. After my son died, I had to learn how to mother both a living child and a dead one. Now I spend Mother's Day at the cemetery, the only place I feel like my whole family is together. I don't specifically remember my first Mother's Day as a mother, over 16 years ago. But I know it must have been so sweet. My husband probably served me breakfast in bed. My five-month-old son William likely had his breakfast there with me too, nursing himself back to sleep. We probably took a walk in the neighborhood, or maybe we drove over the Bay Bridge from Oakland into San Francisco and walked the Embarcadero, enjoying the spring sunshine of the Bay Area. Being a new mom had so much promise and hope, and I'm sure I relished the fact that my husband Nick and I had finally become a family, not just a couple.…