It's not easy adjusting to all tje changes and accepting what new normal is. Menopause isn't easy without it being brought on suddenly like with tamoxifen. It changes how you feel, impacts on your sleep and kills the libido. Never mind adding the cancer fears to it. But things will improve.
As to accepting having one breast...do you have to?. Have you considered reconstruction? . Whilst it will never replace the breast you lost it may well make you feel more comfortable in your own skin. I had a bilateral mastectomy with implant reconstruction...it's not complete yet...but I do feel comfortable with my new breasts and how they look. I am just unhappy with all the weight I gained on chemo...but working on that. I think that the new promotion of promoting scars help women who don't want reconstruction, but it can make those that do feel weak for wanting it. We are not. It's just a different journey but just as traumatic.
Meanwhile perhaps it's time to look at some pretty lingerie. The link I have added have some nice camisoles that you could put in a soft form and wear to bed.
http://www.erilan.com.au/collections/mastectomy-bras-underwear?page=15It will all take time. What you are feeling is perfectly normal. Do you have a breast care nurse? Might be a good time for a chat also.
Take care. Kath x