I can truly understand how this 'forgetting' can so easily happen.
For the last week I have been 'good' and can honestly barely remember how dreadful felt only 9 days ago. It's like it happened to someone else, and all I can remember are very faint echoes. but equally when I'm 'bad' I simply cannot remember how it feels to feel 'good' and it genuinely feels like I have always felt this low and anxious, and that I will never feel anything BUT this low and anxious.
It is so bizarre. It's one of the reasons why I started keeping a Mood Diary over a year ago, so I would have actual proof, in black & white, showing when I felt 'good' and 'bad.'
And when I'm 'bad' I am convinced I will never feel 'good' again, and vice versa.
I know when I was younger and getting normal, regular periods and dreadful PS every month, each month (without fail) I wouldn't think I had PMS this time. And that in actual fact THIS TIME I was perfectly justified in feeing furious that DH had used the last of the milk, and perfectly justified in throwing a coffee cup at him in fury
I would never, ever think or believe that it was the PMS making me feel this way. Until a few days later when I would look back and cringe at how I'd acted. And this would happen month in/month out.