Making The Hard Decisions

BreastScreen Qld used mammogram and ultrasound guided biopsies to diagnose a cancerous lump  in my right breast close to the chest wall which was removed by surgery on 17 May 2019, all went well.  When I went back about 10 days later for the post-op they said they did not get it all as it was unable to be seen on mammogram or ultrasound and I needed to have an MRI and he wanted to check both to make sure there was nothing else lurking in there.  I was booked for surgery on 13 June with the results to be looked at prior to that, if nothing then he would take out the bit missed plus a margin using the current scar.  I heard nothing about the MRI and when i arrived for the surgery i was told that my file said that it was going to be what had been discussed, so I thought great and was relieved knowing that one more surgery plus the radiation and possible chemo and we are on the home stretch.  They were running behind so i waited 2 1/2 hours when the surgeon came to me and described what we both had discussed and i commented that it was great the MRI had showed nothing else, he said he had not seen it but one of his junior doctors had so he went to have a look at it, he came back and said he was sorry but he would have to cancel the surgery as there was a line (mass) in my right breast and he would have to take my MRI pics to the panel the next day and see me on Monday to discuss their findings.  I had been very positive up until then, I was angry and cried myself to sleep that night and the next day was inconsolable, until I decided to get off the couch and get on with my life and not let them beat me.  I was not called with a time for Monday, so Monday morning rang up to check what time and told no appointment had been made and when I explained they made me first cab off the rank for the clinic.  Surgeon showed me the mass which they say is DCIS, I have the option of just getting a mastectomy next Thursday or having an MRI guided biopsy on Friday to see if the mass is cancerous or not and then decide whether to go for surgery to take out the bit they were going to do with a bit more then chemo and radiation or straight to mastectomy and no chemo and radiation.

Does anyone have any wisdom or insight into my situation to help me make this decision?  I am so confused and upset by them upending my world.