Nasal or sinus congestion can definitely exacerbate symptoms of sleep apnea. I have seen this in my own condition and in patients over the years. Many sleep labs recommend that patients actually reschedule their sleep studies if they are sick or congested. As for the allergies, inflamed sinuses can also contribute to symptoms. I had a water leak in a neighboring condo unit at one time, and got very sick with severe congestion and a sinus infection. We eventually found mold between the walls of the condos. Once that was removed, my sinus issues cleared up and my breathing improved. As a result, my sleep was much better as well. Best wishes and please keep us posted on your progress!