Power naps aren't the kind that you're describing, LH. A power nap is just long enough to go to sleep, it lets you relax completely, but you don't then stay asleep. Those long naps are hard on me, like you described, but a 10-20 minute power nap is all it takes. Seriously. Set a timer, you probably won't wake up by yourself in that time, but that's what you need to try.

SRS