Well according to ICD-10 (International classification of diseases) I would call it adjustment disorder. The flashbacks certainly are a part of PTSD, but that usually develops after several months. (I just had advanced training on the subject)
But now to your story. It's good to see that Clark finally feels better. And he's trying to be super already. Way to go, Superman.
I, too feel that this story demands a sequel. I for one would be an avid reader.
