Hmmm, it could be your body fighting off a bug, or it could just be that you're not used to all the proper sleep you've been getting - now your body's telling you "no, not yet - I need moar."
I learned this in Developmental Psych: sleep is like a bank account. You NEED to get a certain amount of it (say 7-8 hours a night) - your mind might be saying "no," but your body says "yes." If you get less than that, you have to make up for the deficit (that's why a lot of people sleep through whole weekends). If you don't, the balance that you're short gets taken away from the end (shortens your life by that much). Your body is probably just trying to catch up on your "overdraft" now, since you'd been going on 3-4 hours. So maybe just go with the flow, and let your body tell you what you need to do...
That is possibly what happened. My brain not wanting to wake up..lol. After sitting down and drinking a couple of cups of coffee the dizziness has passed. It was interesting while it lasted.