Grieving is a part of life. It is a necessary process to go through while someone dear has left us behind.
When death took away someone dear, you probably may have a mixed feelings of:
Shock
Confusion
Denial
( You may tell yourself, "It's not true. This can't be happening!")
Anger
Sadness
Guilt
Hopelessness
It is perfectly normal for you to mourn and cry. You may feel depress for a while. You can seek out for some caring friends, who could understand your feelings of loss and share your pain. Expressing your feelings to others would also help you to overcome the grieving process.
Look for professional help when necessary: If your grief seems too overwhelming, seek for professional help (e.g. talk with your counsellor). Seeking for help is a sign of strength, not weakness.