"Procrastination," specifically, may not be a symptom of PTSD, but avoidance and a low stress tolerance are symptoms, and yes, the struggle is real.
Ditto what Cashew said about making big goals into little goals. I read an article not too long ago that suggested splitting up an 8-hour day into fourths, so that you only had to concentrate on what could be done in two hours. Given my nature (reeeally low stress tolerance when I feel overwhelmed), I have taken to writing to-do lists that split my time into 10- or 15-minute slices.
When I was in school and shit really hit the proverbially fan internally due to PTSD, I actually just had to do things without thinking about any of the things I needed to do. It's sort of hard to explain, but I would just kinda... not think about the mountain of stuff that had to get done--I just blocked it all out--and chipped away at whatever sounded good. The whole crux of it was simply continuously doing something related to school. So, for instance, if I knew I had to do A, B, and C for X class; E, F, and G for Y class, and H, I, and J for Z class, but doing C sounded good for an hour, then doing F for an hour, then taking a little break and chipping away at H and J... that's what I'd do, while consciously not thinking about all the other items I had yet to touch.
I don't know if any of that helps, but I completely understand where you're coming from. I got to the point where I didn't even know what we were supposed to be doing in class... I just winged it and hoped I was reading the right material. :sorry: