I can relate to exhausted. My next race is six weeks out and my mileage is way down from working so much. With the work schedule from now to then, I don't know if I can get more than one long run in, and I've only done two long runs in the last month and both of them not very long. I'm in the middle of working eleven days straight before a day off, and I'll be traveling that weekend, so won't get much rest. I have worn the HRM to bed at night a couple times to get an idea of what resting heart rate really is, since I tend to rev up quickly when I wake up. I no longer take my HR first thing in the morning, because I can usually tell what it is just by how I feel.