I am sorry for your loss, anyone losing a loved one is going to feel down and will need time to grieve. calling your Pdoc may be a good idea.There is no pill that will take that grieving process away it's just something everyone must go through. You can do things to ease your grief a bit. Get outside even if its only for a few minutes, meditation, try to eat healthy, exercise of some sort, walking is great, enjoy something in nature, plant a tree for your Grandfather. Any activity that engages you, allow yourself to grieve but know that you can and will keep moving.