I feel a headache coming on.
Prollly because all my cola is in the fridge (I had guests) and I have only had one can this morning (like a drop in the ocean).
I congratulate myself on noticing so promptly though.
Usually I have a headache for a few hours before I realise why I feel ill at ease.
Well done me.
Now, without further ado, I must find the pain killers..