Mari

I think you should really consider asking them if there is any chance they will consider letting you do this job on a flex schedule, explaining that if they can't you may not be able to fill in for them. That you have a issue with sleep and need a later start time. And then really think on what other issues you might need to have some flexibility on. Put these into the works
too.

If this is something you really would like to consider then go for it.

And if they really believe its a thing were you need to put in 5 days.

Maybe the 5th could be done from home? You know work like paperwork.

Donna