So sorry to hear you are having such a bad experience with chemo. I have been worried for the opposite reason, I have had two doses of the same chemo as you and had very few side effects. I have been worried that this means that the chemo isn't working.
The metallic taste is yuk, can't face certain foods at all now but there are so many foods out there, so I am trying foods I never would have in the past. Chillis etc and very sweet treats, Choc mint slice biscuits, thanks to a friend. I can look forward to weight watchers once I've beaten breast cancer.
I think you are very brave when you have had so little time to come to terms with diagnosis, mastectomy and chemo with Christmas & New Year thrown on top. Be kind to yourself and I hope it gets much better for you.