I’m really sorry to hear what you are going through.

I was diagnosed with Lymphoma, after many years of dealing with a chronic illness without a definite diagnosis. It was encouraging that at least with the cancer there was a definite diagnosis and a clear treatment protocol. And although the treatments aren’t easy they are time limited and it is possible to recover.
I highly recommend the book: Anticancer by David Servan Schreiber
http://www.anticancerbook.com/

I agree with the recommendations of mrsD.
When I started the chemotherapy my hemato-oncologist and the doctor who manage the integrative clinic at the hospital recommended to stop all the supplements I was taking. I don’t know if this recommendation is relevant to the specific supplements and treatment you are about to get.

Good luck !