Sorry to hear about your diagnosis, especially hard at Xmas time with a young family.
Don't try and overdo things when you get home, walking is great exercise as it helps clear the head.
I maintained my fitness up to the week before my surgery.
I was up and walking around the hospital the next day after my mastectomy and walked almost everyday some days just around the block.
After about 4 weeks I was back to gentle cycling. I have started Aqua classes just before Xmas had to wait for healing. I also went back to the gym and did some weights.
My current goal is to keep up my fitness in preparation for the next round, reconstruction!
Remember be kind to yourself,
Louise x