When to shut out loved ones

Like everyone here I lost someone dear, close, and irreplaceable to me, very suddenly and much too soon.

A week out from their death my friends and partner have gently suggested that I move on because my immense grief over it is becoming a burden to their own healing. What are some productive ways to grieve in secret and shut out others from the grieving process so that I can heal in my own time without hurting others?