Don't worry, Pollyj. I have just scrolled up the page twice, to check out your name. The first time I had forgotten it again before I reached the message box. I have always had a bad memory for names and faces. Apparently some peoples' brains aren't as well 'wired' for recognition as most peoples'.
I have been doing many of the absent-minded things that people have mentioned for years. I have also noticed, in the last few years, that I sometimes have to sit and think before I can remember the route to a familiar place. It doesn't really bother me, though. I have managed to get myself all the way to Australia several times in the last few years without accidentally ending up at the wrong boarding gate.
I would be lying if I said that the thought of dementia doesn't scare me a little. It's such a horrible condition. However, I know a few people who developed it, and none of them suspected that they had it. It was the onset of really noticeable odd behaviour that alerted their families and friends. I'm sure that you are just tired and stressed, but see your GP if you need reassurance.
Above all, try to get enough sleep, drink enough fluids and try to do relaxing and pleasant activities. Good luck.