Sunday 4/25 long run, 2 hrs 5/3 7:10 miles

Tough one today, with a first. I didn't make it the whole two hours. At about 1:45 into the run, I suddenly stopped running. I didn't think about it, didn't really make a conscious decision to stop. I was having some difficulty in the previous 2-3 running reps, but I thought I could make it through. Right after I stopped, I felt for my pulse rate. I didn't have a heart monitor, but I'm guessing it was around 200 beats per minute. So my body was telling me something.
There were a couple of factors that probably led to this. First, I was up at 5:15am the day before to volunteer for the Get In Gear race. I was on my feet the entire time up until about 1:30pm. It was cold and rainy, and I was very tired afterward.
Also, I attended an event last night. We were out until about midnight. I got a decent night of sleep, but perhaps I needed an extra day of rest.
Here are my splits for today's long run/walk - 5 minute run/3 minute walk, running at 7:10 pace:
1 - 7:44
2 - 6:30 (I think I over-compensated for the slow first split)
3 - 6:51
4 - 7:02
5 - 7:06
6 - 6:56
7 - 7:04
8 - 7:08
9 - 7:00
10 - 6:58
11 - 7:11
12 - 7:17
13 - 7:10
14 - 7:10 until I stopped at 1:51 into the 5 minute run.