It is very hard when someone close to you dies, so I wanted to provide you with an overview of what Written Torah says about death and how to deal with it.
YLT Gn 23:2 and Sarah dieth in Kirjath-Arba, which is Hebron, in the land of Caanan, and Abraham goeth in to mourn for Sarah, and to bewail her.
As you can see, you should mourn and bewail your dead. This is normal so do not feel uncomfortable to cry and lament. Let your soul express emotion. This will help with healing.
YLT Dt 14:1 'Sons ye are to Jehovah your God; ye do not cut yourselves, nor make baldness between your eyes for the dead;
As you can see, Torah forbids one to mourn the dead too much. Torah celebrates life, not death, so even though mourning is appropriate, it should not consume one's life completely. Mourn your dead and move on with your life. This is the message of the Torah.
Here is what Torah says about mourning time:
YLT Gn 50:2 and Joseph commandeth his servants, the physicians, to embalm his father, and the physicians embalm Israel;
YLT Gn 50:3 and they fulfil for him forty days, for so they fulfil the days of the embalmed, and the Egyptians weep for him seventy days.As you can see, Hebrews mourned Jacob for fourty days because he was embalmed. Egyptians mourned Jacob for seventy days.
However, Torah mourning time was later amended to thirty days:
YLT Num 20:29 and all the company see that Aaron hath expired, and they bewail Aaron thirty days--all the house of Israel.
YLT Dt 34:8 And the sons of Israel bewail Moses in the plains of Moab thirty days; and the days of weeping and mourning for Moses are completed.If death was sudden/accidental, do not blame yourself. There was nothing you could've done differently. God punishes each person individually for his or her sin.
YLT Dt 24:16 'Fathers are not put to death for sons, and sons are not put to death for fathers--each for his own sin, they are put to death.
So do not blame yourself, mourn your dead for thirty days and move on with your life!
CLV Dt 30:19 Today I call the heavens and the earth to testify against you: Life and death I have put before you, the blessing and the malediction. Now choose life that you may live, you and your seed,CLV Dt 30:20 by loving Yahweh your Elohim, hearkening to His voice and clinging to Him (for that means life to you and prolonging of your days) so that you may dwell on the ground about which Yahweh had sworn to your fathers, to Abraham, to Isaac and to Jacob, to give to them.