I am very sorry for your loss. I have experienced losses both anticipated and unexpected. When I was fifteen years old in my first year in high school, my mother died of melanoma at age 54 in December 2004; we were anticipating the loss. As with me, I am sure your loss is emotionally stressful for you and your family.
Your grief may ebb and flow. It has been said that each of us has this well deep inside of us that can be filled to the brim with grief. Every time we cry, we empty out some of the well. But the well fills again. The level of sorrow in your well may lessen as time passes, but it will never run dry. There will always be birthdays, anniversaries, holidays, and those days when the well seems to fill to its brim again. Allow yourself time to remember and mourn. It is part of your healing. Grief is a continuing journey.