Sick and school

Last semester I missed a little bit of school due to my health. I have a low immune system. We are in the second week now and I'm sick again, my throats is so sore and I can't stop coughing. One of the bitchy teachers said " you need to push through it and go to school "

But if I was at school they'd just tell me to go home. I will infect others. Like I'm coughing every minute and I can't focus like this.

What do I do?