Hers 2 Aggressive Breast Cancer - mastectomy in a few weeks. I feel like I'm grieving at the thought of losing my boob. Is this normal?

Hiya  first time posting.I was diagnosed with hers 2 aggressive breast cancer  stage 3 on the 3rd August.  I finish my last round of chemo today & expecting to have a mastectomy in the next 3 wks. All ìve done the last few days is cry at the thought of loosing my boob.  I feel as though I'm grieving. Has any 1 else felt like this & IS it normal for me to feel this way. I was also diagnosed with cancer of the larax in 2000 and had the all clear in 2221. I never felt so low as I do