I also work in a secondary school library and I finished chemo and rads in August 2018. I thought that meant that I was fine but with so many people asking, I decided that I would check. It seems that chemo can have some lasting effects and my last 2 blood tests showed that my white cell count is low. I have not been back at work since on medical advice but I am unable to work from home due to education dept policy. I would suggest that you have a blood test before making the decision but really, if you're given the option to work from home, that may be the best to do.