Struggling at work..30 weeks!

Hey all, I’m a primary school teacher and am supposed to be working another 6 and a half weeks but am already really struggling. I ended up in the hospital at the beginning of the week with suspected preeclampsia but they just said to rest and take it easy which is easier said than done when working with 30 5year olds haha. Just wondered when did other people start their maternity leave/did you end up getting signed off? I love my job but am worried that it’s going to make me ill working right up to the end. Thanks :) x