Original:

A bad day

Today is rainny,and a little cold.I stayed outside all day to finish my work.I felt as if I walked a long time.Iam so tired now.And I am depressed.Fortunately,I completed my work.I hope all will be better tomorrow,as well as my mood.

Correction:

Today is rainy, and a little cold. I stayed outside all day to finish my work. I felt as if I had walked for a long time. I am so tired now. I am also depressed.

Fortunately, I completed my work. I hope all will be better tomorrow, as well as my mood.

Notes:

rainny --> rainy 

Instead of, " I hope all will be better tomorrow, as well as my mood." you could also say, "I hope all will be better tomorrow, especially my mood."

Also with, "I am so tired now. I am also depressed."

You can also shorten: I am -->> I'm 

I think "I'm" seems more natural especially when spoken. 

\^_________^/

A bad day

Today is rainy,and a little cold. I stayed outside all day to finish my work.I felt as if I walked for a long time.I am so tired and depressed now.Fortunately,I'm done with it. I hope all will be better tomorrow,as well as my mood.