So sorry you feel bad. I had a wide area section, not a mastectomy but still, now I am through chemo and radiation and on tamoxifen I can also feel angry and sad. My oncologist said when I was going through treatment I couldn't think well because it was hard treatment. Now it's over and I am starting to feel a bit better, I have to mourn what I lost with getting cancer.
I don't know if it will help but I think of myself as a brave warrior woman with my scarred breast. I know it's different for a mastectomy but I have a strong feeling I am more a woman than before because I have had to be brave to endure this horrible treatment. Anyone who thought woman were delicate little flowers obviously hasn't experienced periods, child birth and breast feeding, let alone treatment for breast cancer. I am not rage when it comes to dangerous things like bunny jumping, yet I coped with cancer treatment (just) and I feel this is very female.
Good or luck and best wishes Karen