Notes
The plan was for an 18 mile run. At mile 15 I started to get dizzy and my vision was a little fuzzy. I finished my water and the last of the "sport beans" I had. I felt better for about half a mile. Then at mile 16 it was getting bad again. When I thought I might actually pass out at mile 16.5 I decided walking was probably a better choice to finish.
Pretty sure I was just severely dehydrated and too hot. Time to start running earlier and taking in my electrolytes I suppose. That was miserable! And embarrassing.