6 Miles on the local trails

I went out to try the local 7 mile loop that I've had so much trouble with lately (only going 4 or 5 miles).  This time I went in the opposite direction so the first 5 miles were mostly downhill.  This resulted in my getting a BIG blister on my right foot/big toe.  After 6 miles it was hurting and also I was starting to get tired, so I walked the last mile home.