I wake up many times during the night. my one nostril is sometimes blocked. how can i know that i have sleep apnea?

Sleep apnea: Sleep apnea is characterized by snoring, and daytime drowsiness to name a few things. Clogged nasal passages are usually a sign of a sinus problem. Sleep apnea is usually diagnosed with a careful history by a qualified doctor, and sometimes a sleep study in a sleep laboratory. Ear, Nose and Throat (ENT) specialists typically deal with sinus problems. Hope this helps!