HI! I have some good news, I passed all my exams.
Allright!! High five :tup:
As for the rest of your post. For me this is a double -edged sword. On the one hand, I have had (and expect will have again) periods in my life where I was popular, sailed through life like it was nothing, went to parties, had adventures that would actually make some people envious.
On the other hand, when things get rough, I "enter a world of pain" (I'm in the mood to quote The Lebowski). It's nasty, I get anxiety, severe grief, exhaustion, rage issues, and when it gets really bad even mild psychotic episodes. When I'm in this phase, mantaining the social life that I had in "happy mode" becomes impossible.
People are less threathened by a happy state of mind. I think at times you can view PTSD as a heavy, black cloak hanging around our shoulders and as has been said above, people can feel that. They don't know what to do about it, they'd rather encourage you to "get over it already" but you can't and then they feel powerless (that's my impression).
Also, when in the bad phase, my brain is so occupied with processing trauma that there is no space left for anything social. I forget everything. I completely lose interest in all the "mundane" things people go through, their world just doesn't appeal to me anymore because it doesn't seem important. All that is important for me is to survive, while they're busy chatting about clothes.
I know it can be lonely. But I'm pretty sure it's just a phase, it'll pass some time. It can also help to build a circle of close friends but I know that's much easier said than done. It took me eight years of living here, but now I have some people whom I have told about the PTSD and with whom I can still communicate quite allright even if I feel messed up.