Forgetting PTSD for some reason

About a week or 2 ago I was sitting in the car with a friend thinking to myself 'if I was going to explain my PTSD to someone, how would I say it?', and then I realised I couldn't remember what had happened to me to suffer from PTSD in the first place. It took me a minute or 2 of scanning through my mind to remember bits and pieces. I even thought to myself for a moment 'do I even have PTSD?'. I tried to think of what symptoms I had, and I couldn't remember any of them (bare in mind that I do suffer to some extent or another almost every symptom because I had it for so long without being diagnosed). This when on for a few minutes until some of it came back to me.
Now ever since then, I remember why I had PTSD, but I still can't remember vividly. I feel blank about it, I know what happened, I know who these people were, I know when and where, but I really have to THINK about it to remember. It feels really vague to me, it's like the information is stored there, but it's some vague memory that I don't have the energy to remember properly.
This has just come out of nowhere, I find it really strange. Is this common? Hopefully what I've just explained makes sense.

I have had this happen with other diagnoses and the pdoc explained that two things can happen. One is that there is dissociation and the mind's protection from the events. The other is actually more like a peaceful resolution within our minds at this moment in one's life that it is not causing an issue and is not in the forefront of our memories for recall and to relive. It is not uncommon or unusual. There may be future triggers that change it, but is a sort of settling of our minds. As far the dissociation goes, that is another story and something to discuss further with a T or counselor.

If it bothers you, I would discuss it with someone. Otherwise, it may just be to that point in this moment that everything is ok. I have been to this place a few times when the events and the PTSD have not been at the forefront, have all but disappeared to some extent like a faded memory, but have unfortunately resurfaced with a venegence in my case. I hope you are having one of those first moments, are ok, and that it continues.

I am wondering if perhaps it is because I have been trying to hide/block it from people that after an incident with a friend where I ended up bringing it up, my mind blocked it from ME? I used to be very honest about it, because it was 'new' to me, I didn't understand what had happened over the years, so it wasn't as big a deal as it is to me now. But as I learned and understood more, I began to hide it, I never talk about my PTSD to people, even if there is something that majorly triggers me, and it causes misunderstanding or awkwardness with friends, I still keep it to myself, I don't say much more than 'unless you know everything about me, you know nothing, you don't have to know what the issue is, you just have to know there is one'. I can't talk about it with people, I feel awkward just saying 'I have PTSD' to someone.
A few weeks ago I blurted some stuff out and burst into tears after a heated misunderstanding with a friend who couldn't pick up on the fact I obviously have issues with certain things. I admitted the next day to him I have PTSD. This was around the same time I had this mental blank (I think was a few days after, but I had known this conversation was coming for a while). So perhaps I've become so determined to hide it that I subconsciously did it to myself?
I know I'm not over it, I don't feel this is a resolution with my past or acceptance. I think it's just gone blank, where I can still remember things, but my mind won't use the effort to think the detail I've always been able to.

In fact, I've just had a light bulb go off, I know what it is that's so odd (or at least part of it), my mind isn't letting me feel the emotion of it. That's the vividness that's suddenly gone. With the emotion goes a lot of detail too. I know certain things, I can mildly picture them in my mind, but I have a habit of procrastinating about my past to myself, and the emotion getting to me. That's not happening, it's just blank.