PTSD would evolve around a certain event in your life that might have happened years ago. Might have happened only last year. The key thing is, when it happened, you got no help for it at all. Thus a year on, or years on, something happens in your life and it triggers memories of that event. It could be something like a car crash. Bullying in school. Abusive relationship. The sort of things people tend to keep to themselves. So try and think backwards if you can. Has anything bad ever happened in your life? Something that might have frightened you at the time. If you can answer yes to this question, chances are it may need to be dealt with now. It may be that you are remembering it more now by triggers.