Motorway Lag

Think I've got drivers lag. Got in last night just before midnight having driven for five hours back from Reading. I think my average speed over the last 36 hours must be around 25 miles per hour. It certainly feels like that. My brain seems to be shutting down and messing around in most annoying ways. I keep forgetting the word for.....thingy..... and walking into rooms and going "I wonder why I went in here" (and it was a lecture too). I was quite worried about impending mental fragility utill I bumped into David, who travelled down with me and is suffering similar symptoms. Here's hoping that tomorrow I'll be back to full strength mental power.