CPAP now reading 35, 40 when it used to be 3 or 5 AHI

Any idea why all of a sudden I am getting 30 or 40 AHI on my dreamstation CPAP machine when it was working just fine & I was getting only 3 or 5 AHI readouts. I’m using fulk face mask that hasn’t leaked. I don’t understand why it WAS working and suddenly just started showing super high AHI. I don’t get it. Help! Thanks!