It has been a while since I've been here as well. Glad you posted. This is a great question. I totally wonder this all of the time because this happens to me, and I wonder if I'm totally losing it!
Since my manic episode in 2002, I have have been suffering short-term memory loss. I forget normal things from before then, due to the trauma of what happened. My therapist/pdoc both say this is normal due to the stress of the event. It is from the stress. I have blocked out almost everything that occurred from the manic episode because it was so horrible, and due to hurting everyone. I have to inquire what happened from my DH mostly all of the time for the definite details so I can understand what actually happened and understand how awful I was, only, when I do, it ends up upsetting me extremely bad. So, that is a trigger for me as well.
There are those around me who will say.."Oh, yeah, I forget things all of the time"- only they don't understand. That is completely different. This is a different scenario. No. It is short term memory loss, blockage of memories, time frames of events, etc... from stressful events to protect ones self.
Do you have a counselor that you see often? The counselor I have now has finally made some sense to me. They helped explain a lot of this to me.
Take care of yourself. I hope that you are able to find some comfort in a good friend to talk to. My DH is a sounding board for me. He listens to me when I need to talk about my memory loss issues, though he doesn't always understand, along with the tdoc.