I bonked today too. I did 25 miles Friday, 25 on Saturday, 30 Sunday, 20 yesterday plus 8 HARD and fast miles on the mountain bike with someone who wanted to hit the trail, and set off to do 60 today (yeah, I know, what was I thinking?). I wound up doing 40 with a friend who is a weaker rider, so I pull the whole way. At 32 my back started bugging me. I stopped and he rubbed it for me, then we set off and it was much better. With 8 miles left I fussed at him to chase me a bit, and I stood up and took off...until 1 mile left, where i totally hit the wall.
Good thing only 1 mile left. My back was killing me and my legs were shaking. When we stopped I stood there for a bit and my friend finally came over and rubbed my back again until I could swing my leg over. He then sort of held me up for a bit until I didn't feel like I was going to just topple over (and I got a little more back rub out of it) and then put the bike on top of the car without being a pansy.
Another friend called to ask if I wanted to hit the trails again...uh, no. I am biked out. Tomorrow is run and lift day.