Scared! Help! Thought the cancer was gone

There was a bilateral mammogram screening in November of last year (I didn’t have any symptoms, no lump, was just purely cautionary). The main findings at the time were that one breast had abnormal calcifications and abnormal mass. Upon further testing, I was then diagnosed with DCIS, and then stage 1A IDC shortly after. Two different masses but similar biology. Grade 1, score 4, Ki-67 6%, HR/PR+, HER2-. Undergone Mastectomy, sentinel lymph node removal, and hormonal therapy. With that they concluded there was no lymph node involvement, only IDCs which they said changes little to nothing. DX score was 14 with distant recurrence chance within 10 years being 4%.

Fast forward to now, had a bone scan, clear. Had another mammogram screening, and now the remaining breast has abnormal calcifications, but nothing about the mass. Was never mentioned last screening, this would have to be new? From what I understand, it’s unlikely here for breast cancer to spread in-between breasts, so this would have to be ANOTHER primary tumor!?

This has me freaking out, what’s the chance this is benign or not??? It is said that calcifications are mostly benign but is that true?? I really don’t wanna go through this again!! I was under the impression that breast was fine due to last year’s screening! Waiting for further testing is so tiresome it makes you just want to get rid of the breast…

Should another Mastectomy be pushed as soon as possible?? Or is this not as concerning as I’m making it out to be?? Help!