Out for the count

The referee is counting, he's reaching high numbers and this time I'm down. I'm done.
I came through the first four rounds of chemo with only glancing blows and my spirit in tact. I was doing it, I still got to live a life largely uneffected by treatment nd in good weeks I was able to be mummy to my girls.
But this fifth round has got me battle weary and for the first time since being told it was cancer I feel very ill. The walk to my daughters school- less than five minutes on foot- physically hurt yesterday and once the girls are out the door in the morning, it's back to bed and to sleep for me until they are home.
I think what  helped get me through the previous rounds is a spell of time inbetween each where I've felt normal. This time though I've not been as lucky and as well as feeling rough I'm miserable and hiding from the world.
I can't hear 'you've only got one to go' or 'you must feel so relieved' or similar (phrases I admittedly would also say to someone else) because the positivity feels so abrasively at odds with how I am right now.
It's not you, it's me and I need to sit out in my quiet corner until I can do the world again.
I have an appointment with my Oncologist tomorrow and I'm hoping above all else I can persuade her to let me off the final round. I don't have another one in me. I'm out.