Has Anyone Else Questioned Whether They Have Made The Right Decisions About Treatment

I was wondering if anyone else has questioned whether they have made the right decision about their treatment.  Iv had my surgery & the plan is radiotherapy.  They did find cancer in a couple of lymph nodes & when I asked the Dr why they weren't considering chemo I was told that because I have had a bypass of my aorta in my stomach there was a huge risk to damage to my heart.  When I had my full body bone scan & CT of lungs, liver, kidneys etc they found a shadow on my lung which they don't know what it is & sometime I'll get an appt with the respiratory dept for a biopsy.  If Im honest my logical mind has always questioned radiotherapy (one spot) V chemo (treating the whole body).  Iv also noticed here that there seems to be a lot (more than I thought) of ladies getting a recurrence at some stage after their hormone therapy stops.  That really frightens me.  The Dr did offer a mastectomy although he didn't recommend it.  I think I was in a daze at that stage & went along with what he said (well he is supposed to be the expert).  Now Im REALLY questioning whether I'v made the right decision.  I don't want to go through all of this again later on but feel committed to the decision I made.  I wont be seeing the Dr till after my radiotherapy is finished, I'm going public.  I feel so confused at the moment & really scared I've stuffed up