We have both had it. Started late October and by mid December were beginning to think that Christmas was going to be a write off, but we finally began to regain our health around December 22nd. By New Year I was on the mend an now feel fine. We did COVID tests and it wasn't COVID
The main problem, cough apart, wasn't so much feeling ill as being totally devoid of energy or stamina. Half an hour of doing something - even preparing a meal and I was totally exhausted and needed to sit down and doze for at least an hour to recover.
DH had it as well. He saw the doctor who prescribed antibiotics for 5 days, which did nothing to ameliorate it and then an xray, which showed nothing. So I didn't bother. I had heard it could be whooping cough, but while neither of us whooped or were sick, we were left brathless and close to retching at times, so I think it likely.
I was speaking to someone yesterday, who had had it and time span and symptoms were similar.
I still have a bit of a cough, but am now rushing around as much as ever. Over the last 3 days I have driven nearly 300 miles, viewed a house, visited a new town and tomorrow we are off to France for a few days. In my terms back to normal. This time last month, driving 5 miles to the local supermarket would have finished me off.