As mentioned by others, you are experiencing a natural reaction to being in a very vulnerable position. It’s time to think about yourself!
Get your health “sorted” with your GP first. Then catch up on sleep and rest. Stay at home for as long as it takes till you feel calmer and less anxious.
Don’t feel guilty you are letting down those back at school. You cannot do your job properly feeling as you do.
You need time to recuperate and recharge your batteries. The past few months in school must have been draining under the circumstances.
I worked in schools for many years...People tend to forget the number of adults and helpers who work in or visit a school, other than the staff&head teacher...There are admin staff, class assistants &helpers, caretakers, cleaners, groundsmen, Playground supervisors, cooks & lunch servers, peripatetic music teachers, some of whom may be “vulnerable”. All are at risk from this awful virus.
I hope you will feel better soon!