Difficult 10km lakeside run

It had been a week after I took part in the 42km full marathon.
Today, I tried running my usual 10km route but I ended up run-walk-jog-crawl throughout the route.
Throughout the run, I felt that my heart was pumping extra hard, I was running short of breath and slightly dizzy..... This was rather unusual for me but I suspected the problem to be the fact that my body has not fully recovered from the blood donation I did 36 hours ago. Less blood = Less oxygen and iron...

I completed the run with a timing of 72 mins (more than 15 minutes slower than usual run's timing). I wondered when my body will be recovered fully....


Anyway,  you can read the article below on the impact of low iron in the blood.
http://pfitzinger.com/labreports/iron.shtml