Update: The smell of smoke has stayed with me all this time (about 3 weeks), although began to reduce yesterday and has remained reduced today.
I saw my doctor today and described the smell, frequency of the smell, the headaches that felt like sinus headaches – and confirmed that I have NOT been congested. He conducted some in-office tests (e.g. follow my finger, tapped on various areas on my forehead and face), and concluded that the problem was almost certainly in my sinuses. He said the symptoms I described are not unusual as precursors to sinus infections, and suspects my immune system may have prevented an actual infection, but if I become congested to come back and he will give me antibiotics.
Yesterday I only smelled smoke for about 4(ish) hours rather than 14(ish), and the headaches have mostly subsided. I am hoping all symptoms will be completely gone within the week.
Oh! And while I had reduced the Gabapentin down to 300 mg – it did not seem to impact the smell, so I am back up at 400 mg/day.
Whew! This has been a trip I don't want to repeat!