Why did you say you were sick and asked for leave?

First of all, explain the reasons directly and clearly, tell the specific symptoms, show the measures taken, make clear the length of leave, show concern for the work, and then say some polite words at the end. At the beginning, you can clearly state that you are unwell. In order to increase credibility and let others know about your situation, you can simply describe your symptoms. Have you seen a doctor or taken any medicine? You can mention that if you know the time you need to rest, you can tell me clearly that although you are unwell, you still have to express your serious attitude towards your work. When you end your vacation application, you should use some polite expressions. For example, I feel a little sick. I feel dizzy this morning with a slight nausea. I went to see a doctor, who prescribed some medicine for me and advised me to stay at home today. I think I need a day off and I can go to work normally tomorrow. I have handled the urgent affairs, and I have communicated with XX for other tasks, and he/she will help to follow up. I hope you can understand my situation and give your approval. If necessary, I will keep in touch at any time. Thank you. "