SG - best wishes as you recover...
I, through my mother, have been dealing with breast cancer for 24 years, but she is alive and doing well at age 74, so your prognosis is very good!
My mother first had bc at age 48 (when I was 18, 24 years ago). One breast, I don't remember what stage, but I know they found it early. She had a masectomy (single), and took Tamoxifen for 5 years, with no side affects. She got cancer in the other breast in her early sixties, had that one removed, same thing, healthy for years. A few months ago, she was diagnosed with cancer in her hip, but it was "related" to the former breast cancers. No surgery, just a few weeks of radiation, and they say she is cancer-free again. At 74, she and my dad were able to leave for their normal 3 months in Florida as scheduled, and although she is still a little tired, she is out there playing golf, etc, just as always.
She has the upbeat, take charge attitude that you have; so I have no doubts you will thrive when this is all over! She jokes (somewhat morbidly, in my opinion) that the next time she gets cancer, she'll already be dead from something else.