Leaving tomorrow but I am signing off sick for my notice period

Hi all, I did a post just now that was probably very confusing and lacked context so I am doing another post here. I’m 30F, been here 3 years, two of which were amazing but the workload this year has been insane.

I wrote a very long termination letter to my director to send tomorrow that was very emotional. It has been an extremely hard time, I have been set up to fail for months and even after acknowledging workload capacity I have had no help. We had a meeting this week where I was penalised massively for multiple things which was a direct reflection of workload. I’ve worked 50+ hours a week to try and keep on top of things but it was impossible and I warned them so many times.

I feel so mentally wrecked and defeated. I am burnt out generally but this meeting has made me want to never return, I have cried everyday since and it’s severely impacting me outside of work.

I don’t want to raise a grievance or take them to court, I want to leave peacefully and focus on my wellbeing and health which has deteriorated. How do I resign tomorrow and sign off sick simultaneously?