What do you think of my writing?????

I didn't notice any punctuation or grammatical errors. The storytelling works very well here, you have my interest and I want to know more. That's always a writer's first goal. The only problem I see in that line is in the beginning the events seem a little out of sequence since "drifting in and out of consciousness" usually follows the point of the diagnosis rather than the other way around. I do have some other critique. There are several pive constructions in this piece. Don't write, "Days, weeks, months ped me by in a haze..." when,"Days, weeks, months ped in a haze.." is more immediate and puts us more firmly in your protagonist's head. Same with, " I knew that she was not my Gran" What you want is, "She was not my Gran." Not, "Feelings of dread and ..." but just "Dread and ...." Again, in the second paragraph, don't use "feeling" if there is a stronger word. In this case I suggest that she "knows" that "each moment was a privilege..." Then the last sentence may be too strong a foreshadowing of something to come. Be sure first that you want the reader expecting something rather than startling them with it. Either can work just let it be a conscious decision of yours. An intermediate approach would be, " I was certainly not prepared for what happened next." I think you have a good handle on this, especially, as I said, the storytelling aspect. Don't waste a lot of time either editing or seeking comment unless you have a complete first draft done. Get all the story out, then start fixing what needs to be fixed. A good writer's workshop would help you. I'll post the website below of the one I belong to as an example of what can be done. Good luck and keep writing.