我需要写一封道歉信给我的老板，告诉他我不能参加会议的理由，具体要求如下，拜求英语高手帮忙！

Hi Daniel Duval, I'm afraid I can not attend the seminar tomorrow ,cause I get a bad headache which has been bothering almost a week. I'll go to see doctor this afternoon , hope everything goes fine.