Chronic sinusitis - sleepy, and fatigue?

I have chronic sinusitis, and I'm always sleepy and tired..can chronic sinusitis be the cause? Or can it be something else? Since I breathe mainly through my mouth, I feel like I don't have great lung capacity or energy..or at times I feel like a have lung spasms and I gasp for air.. I'm waiting on the surgery for my nose (inferior turbinate...) and then I'll see what changes there are.. But other than that - can chronic sinnustits be the cause of all my symptoms and laziness? What advice do you have? Any stories - I can relate to.. Thank you!