I have PTSD (long time running now) and am on Lexapro for the depressive tendencies I have. As for the PTSD, the only thing that I can recommend is therapy. I was fortunate in that I began therapy relatively early (I was 18), and the doctor chose to educate me in the way the mind deals with trauma. I read psychological and psychiatric journals, asked a million questions, and practically memorized the cycle of grief, the cycle of abuse, and any other cycle that had the remotest connection to what I'd been through. If I couldn't be "normal," then I could at least intellectually understand why I wasn't (he did suggest that 2/3 of the worlds males do not wear trousers...what is normal, anyway??)
Long story short: do what you can to understand, even on an intellectual level, what is going on inside your head. That will help you to talk yourself down during those hair-raising moments when you feel you are about to crawl out of your own skin. Discuss your meds: Wellbutrin can have some anxiety-producing side effects, which can jar one out of depression, but does not really help a lot with PTSD (we're already twitchy!).
Lastly, hang in there. Most of these meds can take up to 6 weeks to take effect, and if they are working correctly, you don't really notice it. You just stop feeling "on the edge" and you stop crying at the drop of a pin. You don't really notice it at all unless someone specifically asks you about your previous symptoms. That is a good indication that the meds are working.