Does everybody with PTSD have to have nightmares and/or flashbacks?

To address this post first, I don't have a scientfic answer, but I would say on a personal level, no. I have it, have went through periods with nightmares and other times, without. I have noticed some medications I may take, effects whether or not, I dream. If I focus on something from the past, that traumatic event, I may have mixed thoughts or like visions of past scenes that night in my sleep. If you can understand what I mean. I believe they say our sub-concious mind, dreams all the time. Sometime we wake feeling fatigued, and aren't aware of why. You could have been dreaming.
Hang in there! I'll get to your other post tonight, I just need more time with that one. Don't give up on us!