When can I expect to be back to "100%" after breast cancer surgery and radiation?

As others have said it's difficult to say. I had so much treatment and am still taking Tamoxifen so can't compare with you. Being put under twice takes it out of you, not to mention weeks of radiotherapy. Quite apart from that there may be 'mind' issues as well with your diagnosis. You could possibly be suffering depression without even realising it.

Your boss really has no right to ask you these questions, I hope she never has the misfortune of experiencing first hand what you are going through.

My sister had breast cancer 3 years ago and had the op and 9 months chemo and 6 weeks radiotherapy and she was off work all this time and after treatment was finished it was 3 months later before she went back to work and even then it was too tiring to do office work full time so she cut her hours to part time and is still doing the part time hours 2 years later, Good Luck

That's hard to say. I was back to normal the week after my last radiation session. Everyone is different. Give it a few more weeks.

several months to a year depending on how healthy you were before