hi Sarah, I am in a similar position to you, feeling a bit guilty taking time off work and claiming income protection when I could potentially be at work.
3 yrs ago when I was first diagnosed, I took some time off for surgery but worked through most of my chemo and all my radiation. I used all my sick leave, annual leave and long service leave and made no claim on the income protection I have through my super.
Recently I had a recurrence in my mastectomy scar and found my cancer was now advanced having spread to my skin and more lymph nodes. Having advanced BC has affected me quite differently than EBC. I am so fatigued and often have to sit and rest or take an afternoon nap. Emotionally I am up and down like a roller coaster and don't feel I am in the right head space to be at work. My oncologist fully supports this and has signed me off until the new year, but because I am not having radiotherapy or chemo and have only changed my hormone therapy and started a new clinical trial I feel guilty for being off work!!! So I totally understand how you feel.
However, I am listening to my body for the first time in a long time, and am taking this time off for ME!
When I feel ready I will return to my stressful managerial role....but only when I feel ready.
Much love xx