The Diagnostic and Statistical Manual, Version Five, is a big purple book that should be on your therapist’s bookshelf with the title DSM-5 or DSM-V on the spine. The version five came out in 2013, and this is important for you to know in case you got a diagnosis before 2013 - the clinical definition of PTSD changed significantly from version four to version five. If you see the gray DSM-IV or DSM-IV TR on your therapist’s shelf: RUN. That is some amateur-hour shit.
The DSM-V is the authoritative guide to the diagnosis of all mental disorders. It contains descriptions, symptoms, and criteria for diagnosis. I am stomping my foot for a reason: if I had a nickel for every client I’ve seen who said their base psych didn’t diagnose them with PTSD because they did not score high enough on a “test,” I’d have three or four bucks. There is no “PTSD test;” you have to have a no-kidding come-to-Jesus sit-down with a mental health professional. It takes time and effort. You have to choose to be radically authentic with the clinician, and the clinician has to know their DSM-V. Hence, there are a lot of misdiagnoses out there.
Bottom line is that we all deserve to get our lives back, so find a clinician who understands your diagnosis.