The beginning part of grief that is so much like an actual, physical illness usually lasts no more than 6-8 weeks. After that, the length of time depends on a number of factors, such as the amount of life space shared with the deceased, the degree of dependency on the deceased, and the number of secondary losses.
Secondary losses come about because of the death, which was the primary loss.
I never thought anything could hurt this much. The first is crying, especially if you are trusting enough to cry with another person there who can be accepting of your feelings. The second is talking about your loss and your feelings with a trusted friend or family member, therapist, or minister. When you open your heart to another, their feelings of caring can flow in to your hurt. This is nature's medicine.