It's awful having to make a decision like this and I really feel for you. I never imagined being faced with such a choice in my life. My situation was slightly different from yours in that I chose a double mastectomy mainly for psychological reasons. My Onc and Breast Surgeon thought that medically, my chances were only slightly lowered for recurrence. I had two lumps in the left breast, one TNBC and the other not. Apparently this is rather rare so I had two different plans of treatment. My lumpectomy pathology results showed extensive DCIS still remaining in my breast and it was recommended I have the left breast removed. I couldn't stand the thought of going through all this again in the other breast and they naturally couldn't guarantee that I didn't have DCIS in my right breast. It's apparently very hard to detect unless a biopsy is done. Even then it can be a hit and miss thing. I just didn't want to take the risk no matter how small. So after quite a few months I made the decision to have a double. Turns out that my right breast was clear of any cancer but I still think I made the right choice. It's a tough choice but you are still young and the odds are really greatly reduced for recurrence if you choose a double. I know what I'd do but that is me and I'm not trying to influence you. Talk it over with your loved ones and perhaps see a counsellor. This helped me in my choice.
Good luck with your choice Rachel. All the very best. Love Janey xxx