Any question answered...

how the fuck can I shift this bastard cough that's been plaguing me for the last 18 days?

getting pissed off with endlessly coughing up lung butter like some kind of 60 a day smoker every morning.

Do u smoke?
If yes, then stop.
If no, get copious amounts of honey down your throat several times a day.
Boil in a pot, lemon peel with ginger and honey, put it to a thermos drink it all day.
Don't drink coffee, avoid sugar.