I need to extend my leave until next week

[PRD2021]

I am now down with high fever and flu because of which I will be unable to travel this week.
As per the instructions of my doctor on the score of fever, I need to extend my leave until next week
I hope you will kindly grant me this leave extension.

Please tell me if the sentences above are worded correctly.

 

[emsr2d2]

I am now down with have a high fever and flu because of which so I will be unable to travel this week.
As per the instructions of my doctor on the score of fever, Due to the severity of my fever, my doctor said I need to extend my leave until next week.
I hope you will kindly Please grant me this leave extension.

Please tell me if the sentences above are worded correctly.

Note my corrections above. The underlined section is not clear. Has your doctor said you can go back to work next Monday, or just sometime next week? You need to be much clearer or the person reading the email won't know how many more days' sick leave you're asking for.

 

[PRD2021]

Note my corrections above. The underlined section is not clear. Has your doctor said you can go back to work next Monday, or just sometime next week? You need to be much clearer or the person reading the email won't know how many more days' sick leave you're asking for.

Doctor advised me to take leave until next Sunday.

 

[emsr2d2]

The doctor advised me to take sick leave until next Sunday.

Then that's what you should say in your email but you also need to explain whether Sunday will be your first day back at work or the last day of your sick leave.

 

[Tarheel]

I would probably say that because of the flu my doctor has told told me to take time off from work. (I might add that there is a fever associated with the flu, but that's additional information.)