Is my cockatiel sneezing?

Last night I turned out the light to go to sleep and I heard this sound like "he, he, he". If you make the sound, you have to do it as nasally as you can, and you get pretty close to what I heard. I turned on the light, and she stopped. It happened three more times because I wanted to see if she was sneezing, but every time I went to her cage she was fine. Is she sneezing?