Oh @Red1, these decisions really suck. On balance, I think pulling the pin on the chemo now is probably a wise thing. But only if you'll have no regrets should your cancer return.
At the beginning no one explicitly says to you that we're going to have red hot go at curing your cancer but your quality of life afterwards could be rubbish. There's fine print of course, but at the start most of us are naturally all 'just get this thing out of me'.
I had TC. I had an allergic reaction to the Docetaxel but it was handled with Phenergan and another drug or two. I certainly didn't have the problems you are having, however it got into my hands rather badly, and just over a year later they have not fully recovered (though Letrozole is contributing to that).
At diagnosis my four kids were 17 down to 9 years old. We do have responsibilties outside ourselves that drive these decisions. However, while it's all very well to focus on survival, if you are disabled and unable to look after your family properly, to live your life with the stress and strain that would entail, it becomes a big ask indeed.
I agree with @"~Millie~" unless your team say you must do it, I would not do the fourth cycle. I want to emphasise that's me though, and a viewpoint out the other side of active treatment, as a person having a difficult time in survivorship. Look inside yourself. How much physical adversity can you bear with equilibrium? Will the decision you make, either way, keep you awake at night. Nothing about BC is easy. Big hug, K xox