Why should I work so hard?

After correction from native speaker
I'm on the night shift today. This week, I started work from Sunday to Saturday morning. Of course, I worked the day shift everyday. I'm very tired. I hope I can sleep well tonight.

Original diary
I'm on night shift today. This week, I started work from Sunday to Saturday morning. Of cource, I worked for day shift whole weekday. I'm very tired. I wish I can sleep well tonight.