Hi there. It's a hell of a shock isn't it? All I can say is, five years on, you look back and wonder where the time went. I had a mastectomy, axillary clearance, chemo, herceptin and I am looking at the last 6 months of hormonal therapy (an AI). I was one of the lucky ones who did not suffer fatigue or nausea, so I worked through treatment. I do have a few long term side effects, which somewhat dented my confidence, but all manageable. From this end of the process, there are some things I know helped me, may possibly assist you.
I kept a journal, just on my computer. I found it helped to keep track, whinge a bit privately, remind myself of things. I called it the Bald before Christmas chronicles! I still write in it occasionally. It's just for me so far
Went to a counsellor when I got the third long term side effect. I wasn't depressed, just somewhat confused about who I was any more. Best thing I could have done. Sometimes you need someone else, not a friend or family, to tell you the obvious! Nothing dramatic, just small practices that got me back on track quite quickly.
Got a wig. I was NEVER going to wear a wig. But I did, nearly all the time. An attractive hairdo is a boost anytime, when you are feeling down, over it, and in my case, mono-boobed, it's even more valuable. It was synthetic, easy to manage and not very expensive. And many people I worked with didn't know I had cancer. It was never a secret among immediate staff, but you don't need a big sign for every Tom, Dick and Harry.
This will pass. Things will shift and happen on the way because that's life. and you are still very much part of it. My best wishes.