Dear Principal,
I want to inform you that I am suffering from anemia and food poisoning; as you know that living separately in hostels causes many health-related problems. In addition, due to iron deficiency and other vital nutrients, my skin has turned pale, and I constantly feel dizzy and tired in every class. As a result, I have not concentrated entirely on my subjects.
The doctor advised me to complete rest for one week and a suggested diet from a dietitian. Therefore please grant me leave for this week from _____ to _____ so that I can recover as soon as I can before the examinations are due. Also, please ask the teachers to cooperate with me by giving me ten to fifteen minutes extra from their schedule if I cannot understand anything.
I will be thankful to you for your kind consideration.
Regards,
Your Name