However, I kept everyone running, I sent no one home, because these intervals were not about time, they were about effort. Even if you weren't hitting your times, as long as you were running fast, you were accomplishing the goal of the workout. To train your body to effectively run at high speeds without experiencing a total shut down, both metabolically and structurally.
So yeah, it was a tough workout. But it was a beneficial one. (Hopefully you made it even more beneficial by resting, hydrating and eating well last night!) Today is going to be a tough workout too, 90 min run, at a pretty good clip. Take advantage of these tough workouts, soak them in, embrace them, attack them; and you will be that much of a faster runner for it.