It's been a very long time for me, I usually do a good enough job of pacing myself. Almost forgot what it feels like.
I had a hilly 40 km planned for tomorrow, the weather forecast said do it today. Wasn't really ready but beggars can't be choosers when the sun is out anywhere near Seattle. The snow was nice and firm, everything felt great. I was skiing 10 minute miles, which isn't bad for the amount of elevation gain.
Almost two hours in, I suddenly go from feeling great and having fun, to feeling like somebody just punched me in the stomach and I need a nap after I puke. Light headed. Still more than 10 miles to go and I haven't even climbed sick joke hill yet.
I might have been able to finish if I didn't know that (and slowed down). But my brain said F this. So I made the call of shame, skied down to the road, and DNF'd. Overcooked an easy corner on the way down.