It was a good story. But:
(I know, you could see that coming a mile away.)
Their reconciliation happened pretty fast, didn't it? I mean, here's Clark with all this emotional baggage - the kind of baggage that doesn't disappear after six weeks of therapy - and now Lois is willing to move back to Metropolis with her kids and live with him? I think they should have talked it over more, maybe gone to some joint sessions with Dr. Friskin, worked through some of their residual anger (with each other and with their respective situations), and maybe THEN consolidated the move.
The problem some people have with fan fiction (I'm not one of them, mind you) is that the ending is pretty much pre-determined. In this story, we all knew Clark and Lois would get back together, but it's the author's challenge to make it hard, make it look like it's not going to happen. It would have been easy to add some scenes with Paul, maybe even one where late one evening Paul shows up unannounced on Clark's doorstep and finds Natasha there working on a story with Clark. We know it's innocent, but Paul doesn't, and he threatens Clark and Natasha jumps in to defend him and convinces Paul that she and Clark do have something going on.
But don't get me wrong! I liked the story, and your courage in tackling a touchy subject like PTSD is laudable. I didn't like the part where Clark scared Lois (because I don't like women being hurt), but it does belong in the narrative and it's a natural development in the plot. I seem to recall that this is your first stab at fanfic, and you did a good job with it. Keep it up! I expect to see more good things from your word processor, and soon.