Just checked out the C 2 5k site (link at right) and found that I should be running 90 seconds and walking 2 minutes. No freakin' wonder I'm tired! Oh well. Probably won't adjust it much tomorrow since I've already done it wrong twice.
Next week: intervals of 90 seconds running and 90 seconds walking then 3 minutes running and 3 minutes walking. I'll definitely need a watch. And a whole lotta guts!