Fungal sinusitis

Could I have gotten fungal sinusitis from cpap humidifier?

Doubtful...unless you had a bunch of mold accumulated in the humidifier.

I would think yes!!! if fungii were present in the humidifier chamber..

I think it could be possible. Do you use distilled water?

Unlikely. But keep everything scrupulously clean anyway. Do use distilled water if at all possible.

Catching it from the mask is more likely. There's "face goo" on the mask, it stays wet, and fungus could grow if you don't clean it often enough or well enough.