英文的道歉信（由于缺勤写给老师）应该怎么写！！急！！

英文的道歉信（由于缺勤写给老师）应该怎么写！！急！！今天是这位老师的第一节课，但是我由于起晚了而缺勤了，同学告诉我他留下唯一的联系方式是邮箱，所以准备写一封道歉信发邮件给他，但我从来没有写过道歉信不知怎么写。
十万火急，如果需要其他奖赏请告诉我！！！

Letter of Apology
Dear MR/ MS (加上老师的名字):

I am XX(你的名字） your student who was absent from class this morning. I got your email address from my classmates.
Sorry for what happened this morning， But I am not in mind to do that. After I got up，I prepared myself to go to class, but my stomach felt uncomfortable at that moment and then I went to the infirmary，that's why and how my absence occured.
No matter what kind of reasons，facts are facts， I was absent. It must cause a negative effection on other classmates & teachers，I really wish I can get your pardon and I promise it's the first time while it's the last time to be absent.
Your sincerely student XXX
日期
总不能就说起晚了吧，总要找个小接口说一下，态度摆端正，应该没那么严重。 祝好运！