Advice for persistent cold

I have had a long running cold that I would like some advice on.

The cold started about a week ago and came on very very gradually. Started just as irritation/inflammation in back of throat. I did not actively treat it but used oscillocoxinum.

After the first few days it developed gradually into a mild cough and then a deeper fatiguing cough. It became a problem because each cough would trigger a headache like my head was going to burst from the pressure of the cough. Also there was right sided nasal congestion and sinus pressure. I briefly repertorized and tried Nat Mur 30C.

The headache aspect improved but it felt like the cough got deeper. I noticed the cough was worse when I lie down in my bed at night and the cough would come on in deep hacking bursts of two. So I switched to Pulsatilla 200C.

Again there was some general improvement but the benefit stopped at some stage. Now there is a hacking, fatiguing, dry cough. Very little expectoration from throat. I stopped Pulsatilla because I thought there was no additional benefit. The symptoms have changed a bit because while I have a deep dry cough, it is not in bursts of two but small sustanined longer bursts.

Weather has got colder outside and symptoms definitely seem worse when I go outdoors. Similarly warmer food and drink agree with me more. Not much appetite, I have had only one meal all day. But not hungry either.

Nasal symptoms are also marked: From the beginning it was clearly right sided with blockage on right side and sometimes nose drips a bit on left side. But not a lot like alium cepa, just a slow but constant drip. But infrequently every now and then it reverses and the right side congestion clears up and the left gets congested.
When that happens it is usually accompanies by sneezing as if the air I am breathing is over inflamed tissue in my right nostril.

If anyone can suggest a remedy or some line of approach for this I greatly appreciate it.