The Wall Part 2

Today was the first day I cut a run short. Session 7.3 was supposed to be a 22 minute run, then after a one minute walk another minute's run. I started off well, and after 1.5 miles felt pretty good and strong, but out of seemingly nowhere after 2 miles my legs went and I felt cramped in my side and stomach. I am pretty sure it was down to not drinking enough water over the last 2 days and being generally pretty stressed. I am going to try and do 7.3 again at the weekend, and have a 3-day rest, which I haven't had since I started this routine.