R.S.
I would think about pertussis. Back in the day, it used to be called "the 100-day cough"...a relentless, dry, hacking cough that just goes on and on. Many people do not know that pertussis is actually nearly endemic, since most adults were vaccinated as kids but lost that immunity as adults. About 5 years ago, a campaign was launched to revaccinate adults, but that has been slow going. Pertussis, or whooping cough, may not present with the usual wheeze or whoop like you see in the commercials. It may be a simple dry cough. It is fairly harmless to you IF you are healthy, although it can disrupt sleep and therefore make you feel tired. It can be a problem for young children and especially infants (it can be fatal). BTW, I work in the medical field as a pediatrician, that is how I know about all this stuff. We pediatricians know a lot about pertussis; adult doctors may not know as much since they don't see this disease as often as we do.
You can get tested, but if you have already had the cough for 3 weeks or more, there is a high chance of a false negative so it may not be worth it to you. Only thing, if your children start with a similar cough, quickly bring them in to be tested, just to be safe. Good luck.