It's because my confidence in my ability as a writer fluctuates.
Eng 318R killed my confidence this time.
I learned that I cannot write fiction.
So I've stopped for a while. I'm taking a breather. Waiting for my words to come back.
My dad tells me that I need to get used to it, if I want to be a writer. Criticism is inherently connected with writing. Or any sort of creating really.
I'm working on it.