"I draw on a pot that represents that death of my grandmother." Why is it the personification of loss?

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.