Overtrained or under iron

I am exhausted.

Aside from that, my legs feel dead about 3K into a run. My pace is reasonable, so I know it's not me starting out too fast or too fast a pace. On my 18K long run on Saturday, I was pulling from an empty tank by the last few KM, with the last KM being a very tough slog. Mind you, I shouldn't have left a hill for the end of my long run - that was a really stupid decision. But even then, I had to really push myself to finish that run and not pack it in at 15K. When I woke up on Sunday, I looked pale and sallow, with very dark circles under my eyes. I get wanting a nap after the run, but I feel way more tired than I think I should be. Certainly there's different food/nutrition/hydration tweaks I could make, but this feels different.

My pace on shorter runs is suffering, too. But my heartrate is okay and my body temps are normal, if not a bit lower than normal. I ran 7K at a reasonable pace, and I'm so tired today that I need toothpicks to keep my eyelids open. I'm tired and winded walking up a flight of stairs.

Am I overtrained? I doubt it. I'm doing reasonable mileage and mileage increases, with reasonable paces. I've got lots of rest days. My only specialty workout is hills, and even then I'm only able to do 4 or 5 repeats and I'm so beat afterwards that I want to stop running. In the Fall I was up to 8 or more repeats and felt strong. The thought of adding in speedworkouts makes me want to puke... I can motivate myself to run hills because I enjoy the challenge of the workout.

I'm thinking that maybe I'm anemic. I got my last panel from October and the hemoglobin was on the lower end of the spectrum, but still in the acceptable range for an adult. I've significantly increased my mileage since then. I think I need a doctor's appointment, stat.