I could use some veteran runner advice or insight here.
Lately my legs have been very tired. While running, they feel heavy and start feeling sore much sooner than usual. I've been training this winter for track, on average about 30 miles per week. Usually every tuesday I do 6 800m repeats. Two weeks ago I did 7 800s at 2:58 pace. Today I did 5 at 3:06 pace and felt so much worse than previous workouts. I've tried taking a day or two off to see if I'm just overworking myself, but that didn't help and honestly that kind of mileage doesn't seem high enough to really wear me down. Even walking up stairs is making my legs ache. Hills are much harder than usual, and this past Saturday I went to a casual pre-track invite, where I ran a 6:08 in the 1600. I haven't ran that kind of time since middle school! Last year I ran a 5:15, my slowest a 5:35. The thing is, my breathing and heartrate never get out of control, it's just my legs that start feeling exhausted.
For a week or two I was getting less sleep - around 5 or 6 hours a night, but for the past few days I've been getting around 9 to try and kick this fatigue. I gave blood two weeks ago and at that time was told my iron levels were decent. I've started taking a multivitamin and iron supplement daily for the past week to try and get out of this rut. My diet isn't always the best - I've been eating lots of chocolate - but I don't think that would do it? And other than that, I think I eat fairly balanced meals.
Any thoughts on what could cause this kind of tiredness? I don't want to start my senior year track season with low energy and slow times, especially as I'm talking with college coaches. I know my body, and I know that I'm not exaggerating this feeling of fatigue.