I write this email to inform you that my name is _________ (name) and I am a resident of _______ (mention address).
I would like to bring to your attention that from the last ______, I have been suffering from ____________ (fever/headache/cold/pain/any other). Therefore, I request you to book an appointment under my name at the earliest.
It would be so nice of you if you could respond to this email at the earliest and confirm the booking made for the same. If you need to contact me, you can always feel free to contact me at __________ (contact details).
_____________ (Contact Details)