WFH accommodation

Writing this at work while I sit in excruciating pain. My workplace recently implemented a strict RTO (return to office) plan of 4 days a week with the plan to move fully in office next year. When I started it was only 2 days a week so it was easy to miss a week and make it up another time. However, having undiagnosed endo and a chronic illnesses it’s hard now to miss days for my period each month because I’ll never make them up. For 3-4 days before my period I’m in pain and then during my cycle I’m usually bed ridden trying to work from home or out sick. Unfortunately because of endo and a chronic illness my sick leave balance is non existent because I use it almost right after earning it. I’m on a 2-3 year waitlist to see Gyne for just a consult in Canada.

I’m seeing my GP next week to ask for a doctors note to be able to work from home the 2-3 days before my period and during my period. So approximately 1 week per month at home. Has anyone else pursued getting an accommodation to work from home some during the month because of endo? Do you have any tips or recommendations for approaching this? My workplace does have a duty to accommodate mandate and I’ve watched 5 members of my team that are pregnant get approval to fully work from home for the last 5 months of their pregnancy so I don’t think me asking for 1 week a month will be an issue. But just really nervous about the whole process.