welcome to beyond blue.
sorry to hear about the loss of your Nan - no word that I can say would take away any of the pain you would be feeling.
someone I knew died recently - this was when the restrictions were coming into place. A funeral for 100 became 25 then 20 then 10 people attending and then not at the church where she wanted the funeral. many people that wanted to attend could not.
so the feeling that you have at this time would be natural. It sounds like you were very close to her. Overcoming the feeling of grief and loss will take time. And if you feel you need to talk to someone, you could do that here, or seek professional help. I don't think it is something you forget but one day come to terms with. There are also things you can do to keep her memory alive as opposed to a loss... writing a letter to her, or having some photos of her, doing something she liked to do. Remember we all have our own ways of dealing with situations, there is not right way or wrong way, only your way.
Listening to you,