求一封220-260字的英文道歉信（INFORMAL的），在线等，急

Dear Peter,

How are you doing, and how was your birthday?
I apologize that I couldn't attend to your birthday party last night. I was sent abroad on a difficult assignment by my superior accidently yesterday. I know I should have told you about it, and I know that I let you down badly. But I really didn't have time to make a phone call, and this assignment is highly classified. I was shocked when I got the message to the overseas. I tried very hard to get rid of it, but I couldn't. You can hardly imagine how much I miss you. I haven't seen you for about two months, I wanted to see you eagerly just like a cat on hot brick. But please trust me, your birthday is stamped in our memory, and I will never ever forget it in my life. I'm trying to work hard is only because of you, I want you to live in a world of perpetual happiness. I want you to be my prince.
My darling, I will be back home after two days, and I promise I will bring the birthday pr