Work affecting chronic health condition

Bit of backstory: I have rheumatoid arthritis severe and I am currently going through IVF.

I am an administrator at a construction company since October 25. I chose an administrator role as I wanted to take a step back in my career to protect my health more.

Over the past few months I have been struggling as the pressures of the role are not what were advertised to me at the start. The role requires at least 2 people for the workload but there’s only me.

I’ve recently had 2 weeks signed off due to my ivf treatment and I have returned to a 2 week backlog plus my daily tasks. It is completely unmanageable. My rheumatoid has also flared badly due to my ivf treatment and I have been to hospital twice this week for steroid infusions to try and avoid a hospitalisation.

I have reached out to management this week for help as I feel as though I have no choice but to leave for my health. Little support has been provided.

If I were to hand in my notice can I legally resign with immediate affect due to my health deteriorating drastically? I have a 1 months notice period but I will end up in hospital if forced to work the month.