Crazy numbers last night, not sure what happened!?!?

So I went to bed as usual last night. I woke up at 12:30 am needing to go to the bathroom (drank alot of fluids last night). On a whim, I decided to check the LCD screen of my machine. It read:

Leak - 0.00 L/s
AHI - 24.7
AI - .6
HI - 24.1

Not sure what happened. I've never had numbers like that, not even in my first sleep study. So anyways, I went back to sleep. I woke up at 4:30 and felt lousy. Had the chills and felt lousy. Fell back asleep and woke up to my alarm but decided I just felt too sick to go into work. My wife lined me up with a couple of more blankets and an hour later, I woke up for the last time. These were the numbers I ended up with:

Leak - 0.00 L/s
AHI - 9.8
AI - .2
HI - 9.6

The night before, my numbers were:

Leak - 0.00 L/s
AHI - 1.9
AI - 0.0
HI - 1.9

That's representative of the numbers I usually get. Anyone ever had freaky number changes like that? Nothing changed from one night to the next. Weirdness...

Catching a cold? Lots of congestion? Sleeping on back?