Hello & Welcome, Xiao Shu.

Grief over the loss of a beloved companion is wrenching. I'm sorry for the passing of your friend.

It is obvious you deeply cared for your cat and went to great lengths to battle his illnesses and make him comfortable. Your sense of guilt is intertwined with your grief, a grief that may be tied to depression or developing depression. Is it possible for you to relax your mind so that the sense of guilt can unravel itself?

Please make yourself at home here. Consider visiting the Grief and Loss Forum.