Your message under the 'Message of Hope' thread did not go unnoticed. Three months is a short period for grieving. Getting through the holidays is hard. This time of year many hospices (and even a funeral home here) have memorial services and seminars on Getting Through the Holidays. "When Holidays Hurt" is the name of the funeral home's program here. Call a hospice in your town and see if they have anything to offer, it's usually free to everyone, not just families they've served. Also the local mental health office may have something.
You need not pretend that everything is 'normal' -- it isn't the same as previous years. Start some new traditions with your daughter and grandchild. Make a laundry list of things to do. Check off the ones you get done, cross through the ones you can't do. Know that you're not going to have the energy you usually have, and take care of yourself.
You're not alone and we care.