So far today I have spontaneously woken up before 9am, un/loaded the dishwasher, and made myself pancakes (using batter from the freezer; thank you, past Alex). I do not feel a pressing need to immediately go back to sleep.

Yesterday, I swapped over which brand of fexofenadine I was taking (Chanelle Medical to Dr Reddy's, self), had an afternoon nap, and woke up feeling actually refreshed.

I don't care if this is entirely placebo effect, I'll take it.

(I'm pretty sure it's not, though -- I think my post-nasal drip is also reducing again. So.)