Sympathy to all of you. Everyone has given excellent advice.
But reading all of this makes me think that there is something wrong with me. My first experience with the death of a close relative was when my uncle died suddenly at age 52 from a heart attack. I flew across the country for the funeral, which was all about supporting his family. After I came back, I had momements of crying for no reason, or just thinking about him (my aunt and uncle lived with us when I was a kid, for about 2 years). But, the busyness of life took over and it didn't last long.
When it was clear that my mom was going to die from a failed liver transplant, I prepared myself by mentally picturing the funeral and what it would be like when she was gone. Since she was positive during her illness (she even spent time in the hospital, teaching medical residents how to improve their bedside manner, as part of a special program), I decided to be positive. I had a few moments of sadness, but that was about it. I remember her the way she was... happy, active, and a great mother and grandmother.