Bilateral breast cancer anybody???

I have just had right mastectomy 6 weeks ago with axillary dissection. Hormone pos. Said i was T2, stage 2. Grade moderate borderline high eg 2/3 . 2/3 but 3/3 for tubules. One pathologist said high grade so now not sure and i guess not that critical. Total was 7/9. I was sure i would have chemo followed by anti hormone, given size and grade. So i was really shocked and suprised and also worried that i wasnt going to have chemo. I thought it was a given. My onc said chemo would kill me before cancer ! I have a problem with chronic kidney infections and a chronic open wound (pressure /bed sore)  although youngish i live in a nursing home with paraplegia.  I was previously told the large communal living environment had a high risk of cross infections ie nurses.  He said serious infection was almost a certainty. So he just put me on tamoxifen and said would have 6 weekly checks for 3 years then 3 monthly.  Does this sound reasonable? Im concerned as the tamoxifen wont actually kill lingering cancer cells.  I was also worried as heard that tamoxifen wasnt as effective as arimidex if post menopause. But as i have brittle bones he said that id go from a paraplegic to a quadraplgic if on arimidex as would worsen my bones. I just worry that the plan is so different from what i have been reading