To me it sounds more like you have PTSD then a personality disorder. PTSD can be very random. You can be find one day and them BAMM!!! for no reason it seems life is to demanding. Then you start to get clingy, or have panic attacks, or depression like symptoms. All it takes is one last straw to break the camels back so to speak.

Finding a therapist would be helpful and you can unload some of the things that have occurred in your past, weather it was during childhood, or adulthood. Sometimes PTSD related things don't really emerge until you are in a safe and committed relationship. After you feel safe, after you are beyond your early to mid 20' and your hormone levels even out things sometimes come to light and cause us issues.