Freaking out about Mastectomy

Hi can see a few familiar names here so thought would pop into the conversation and maybe get some more advice. I was diagnosed a little over 3 weeks ago with grade 3 idc. Had my mastectomy late yesterday so.pretty darn sore!  Cant even lift arm but i guess thats normal. Thing is i was only meant to have sentinel node removed during the mastectomy but when i woke up and asked why i couldnt lift arm, the surgeon said that he noted a number of enlarged auxillary glands so took them too? All of a sudden I'm starting to wonder if i will be lymph node pos as had convinced self that would just have sentinel node and be negative. Always the optomist lol. Now im wondering if it doesnt come back neg will need chemo also and not just the hormone treatment. You dont have chemo if lymph nodes are neg do u ??? Is it not so great that he had to take more than sentinel as were enlarged ?