cough won't complete---whooping cough? iatragenic?

[polly22]

Eight days ago I caught a bad-cough virus from a sick relative, and three nights ago it became worse. Cough is productive but sputum/phlegm is white (so far). I am 69. These past three nights, I can barely sleep for the coughing, and--1 time the first such night, a few times the next night, several times and much worse this past night--a cough will start but not complete itself; instead it becomes a whoop or loud groan and inability to close my mouth or stop the "arc" of the cough; I can barely breathe, perhaps am not able to breathe, while this goes on. So far it only happened while I lay trying to sleep (with 4 pillows now but still less elevated than if sitting up), but last night even turning over, sitting up, crawling out of bed--nothing--stopped it for a long, long moment. I am wondering if I might have whooping cough (but my relative is over his virus with no complications). Or could this be an iatragenic reaction to the expectorant cough medicines I have been taking?