Anniversaries - Some people find that they may do well for an entire year only to find themselves virtually incapacitated by grief during the days surrounding the anniversary of the death. You wake up one morning with a heavy feeling, not knowing exactly why you feel so burdened. Then it hits you the anniversary of one or another dates you shared with the deceased in the past. On the anniversary of the day of death, many grievers report a short-term depression. It's not uncommon to experience discomfort, sadness and depression for a couple weeks before and after the date of death, each year.
Some religious traditions have a requirement around the one year anniversary of the death.
You are expected to need to discharge extra emotions during those days. The headstone is unveiled at this time. Even if your religious tradition does not dictate it, you will feel some deep or extreme emotion on the anniversary of the death. Try to look at the anniversary of the death as another opportunity to grieve to feel some of what has been unexpressed up until now. Of course there will be others depending on your relationship to the deceased.