Girls, question about the wonderful from the wonderful: maternity leav…

Girls, question about the wonderful from the wonderful: maternity leave! I'm a teacher in 2nd grade. Doctors have scheduled leave starting December 20th, employers said they can't allow me to work until then. But I noticed that I'm sent home a week earlier... so I don't know what to do: tell the doctors and ask for another week or go on December 20th? The thing is that there's nobody to replace me yet, the kids will be left behind, and the deduction from my salary for the month is colossal. In general, it feels like always lazy, but I can still work...