all in my head

[frindle]

Hello.
The girl in the story below has a stutter.
She oftens write the word, terrible when she writes a letter to her pen friend. I'm wondering what the underlined part means exactly in this context. Please help!!!


<Now I can tell you why I used to write it(terrible) all the time
because it's one word I can't say.
It just won't come out. It's the most terrible word.
Mom says it's all in my head, because that's what people always told her.> (Her mom had also a stutter when she was little.)

 

[Raymott]

Hello.
The girl in the story below has a stutter.
She oftens write the word, terrible when she writes a letter to her pen friend. I'm wondering what the underlined part means exactly in this context. Please help!!!


<Now I can tell you why I used to write it(terrible) all the time
because it's one word I can't say.
It just won't come out. It's the most terrible word.
Mom says it's all in my head, because that's what people always told her.> (Her mom had also a stutter when she was little.)

It means, "it's psychological". It has an emotional, rather than a physical, basis.
"I'm sure I have cancer, but my naturopath says it's all in my head."