I do not want to work today. Can you imagine a disease which makes me sick for three days and formulate an email for my boss that I cannot work for the next days?
If you are feeling unwell and need to take time off from work, you can consider drafting an email to your boss that conveys your situation honestly and professionally. Here's an example email that you could use as a starting point:

Subject: Request for time off due to illness

Dear [Boss's Name],

I hope this email finds you well. I'm writing to let you know that I'm feeling unwell and need to take some time off from work to recover. I have been experiencing [symptoms you are experiencing], and based on the advice of my doctor, I need to take the next three days off to rest and recover.

I understand that my absence may cause inconvenience for the team, and I apologize for any disruption this may cause. I will make sure to provide updates to [person you will be working with] on any urgent matters that require attention during my absence, and will do everything I can to ensure a smooth transition back to work when I return.

Please let me know if you require any additional information from me, and I appreciate your understanding during this time.

Thank you for your time and consideration.

Best regards,
[Your Name]