Should I feel guilty for not going back to work?

I have Covid-19 and my isolation technically ends tonight at midnight. However, I’m pregnant and I seem to be taking a while to get better. I’m still very weak and I have had to lie down after doing small tasks such as washing up. I’m a teacher and the headteacher didn’t seem pleased at all that I won’t be going back tomorrow. Now I feel really guilty and I wish I’d just not said anything and dragged myself in. Multiple staff around school have Covid because some staff have been asked to cross bubbles quite unnecessarily. I went back too soon after my miscarriage due to being made to feel guilty and I ended up laid up for a few days after school finished (I’d been back for two days). Should I have just gone back? I feel so guilty now. 😩