WHY do they call it a "fast"?

After being upandown most of the night, with one memorable occasion where I reached the head of the stairs, turned and headed right back down again.
After "Embarrassing" myself awake at about 05:35, I resolved not to eat today. Ye Gods "Fast"? It's been the slowest day on record.
Got over the doorstep to note the pond was now full. Due to a strange set of circumstances it slowly empties, but only when the waterfall runs. Investigation shows the ground beneath to be tinder dry. DUH?!?!?!?
Early last month it was totally empty and un-shot, on the 24th it was 6" lower, shot and un-Blipped, today it's as full as usual.
I'm delighted to report I haven't "been"all day and actually dared to "pump". Strangely, no trace of vomiting, which begs the question ... What the hell have I got/had?

Gaffer joined in by getting up, taking station on the settee and proceeding to join the hunger strike. At tea-time she thought she'd try a slice of toast with cheese on...One mouthful was enough, scraped off the cheese, tried again, one bite and that was it, it's still lying beside her.
:¬((

Roll on the morrow.