I usually get what I call dead legs when I up the mileage without tweaking my diet - i.e., I thus end up not eating properly enough to fuel my runs/workouts. (Dead legs = physically feel fine but my legs feel utterly fatigued). So, you may want to look at your diet and ensure that you're 1) eating enough, and 2) getting the nutrients that you need (perhaps you should take a multivitamin depending on what your diet is like?).

If you don't already, you might want to begin stretching your lower back, hamstrings and calves regularly after your runs. (A tight lower back contributes to tight hamstrings and calves). I'm guessing your body is still recovering, based on your comments re leg soreness/stiffness/fatigue.

If stretching doesn't resolve your leg soreness/stiffness and your legs still remain fatigued despite changes to your diet, I'd ease up on the mileage, take it easier on your runs, or cross-train.

No problemo - glad to be of service!

Oh yeah! I forgot to mention, icing your legs may help ease the soreness and speed up the healing process...

Hope you feel better soon!