I would say that your drawing is actually a symbol of your grandmother, not that the act is personification of loss. To personify loss, you would have to give loss human characteristics, like the ability to cry or scream. If you were writing about loss, you could easily do this.
This is a symbol of your grandmother or the idea of the loss of your grandmother because symbol is the term we use when an object represents something else. The drawing may be a picture or image of your grandmother or it could be graphics that represent who she was. Either way, that depiction is functioning as a symbol, a representation.
I guess if you have to use "personification of loss" then you could argue that you are not at work, but the Loss that is in you has been given the human ability to draw. That would be personification of loss.