I'm getting old. I must be - after just one night of sleeplessness I feel like someone has removed my brain with an ice cream scoop and replaced it with damp wool.
I used to be able to survive on very little rest; about 15 years ago I went without sleep for a week to see what it would be like.
Now, just the thought of that fills me with horror. I feel like my blood has been replaced with lead after one night.
I'd give my left nut for some sleep (metaphorical - stay away from me with scissors).