That is what it is called and it is illegal. Let them know that they are breaking the law if they do not accomodate you.
If they fire you anyway, you have a case of Wrongful Termination and Americans with Disabilities Violations. Contact an attorney immediately. In the US, we have ADA laws. If you are terminated for a medical condition, you have 90 days after termination to sue for ADA violations. Many companies don’t want you to know that any help is available to you. They are supposed to offer you help and accomodate your medical issues, not fire you.
Nate has a wrongful temination case pending. He was fired also.