a mystery

Yesterday evening I biked 20km, and enjoyed the ride, after the stormy weekend!
This morning I woke up and my legs were feeling heavy. I had planned to do a brisk 20km+ session, but instead I opted for 19.5km at a slow comfy pace. at least I managed to do the last 3km in 14:10.
It was no mystery to me why I was so tired. For nearly 2 months I have been averageing 125+km every week, incl tempo or speed sessions. Combined with biking... and callisthenics... and power walking... and going to work by bike... and taking the stairs to the 20th floor every day...
Hmmm... It is time to get some rest - or maybe decrease the mileage to 100-110km for the next two weeks and increase speed.