修改好的如下：

This weekend was indeed a bad weekend. First of all, I have been unlucky suffering from a bad cold. Generally, I feel really weak. Moreover, I have a severe headache. For the entire Saturday afternoon, I lay in bed. I did not even eat dinner that day. Until the next morning, the condition seemed to improve. I had to get up and finish my homework. Oh My dear God, the chemistry teacher made us write two papers! Since we did not manage to do well(is this what you were trying to say?). In my opinion, chemistry papers seems like the Devil……Hope that tomorrow everything will be better.

According to the teacher in class, we will have a new classmate coming tomorrow. We certainly welcome him to join us.

新结尾：Well, after all we are students and should try our hardest in completing academic tasks.

祝你早日康复。