Can somebody please explain 'recovery time?

I have just ridden four days in a row, quite hard rides, before I go to work for midday, about 1.20 minutes and averaging 12 miles.

The terrain is mainly off road with a little on road, quite a lot of small hills.

Today was the 4th day and what a struggle, my energy was non-existant.

Is it advisable to perhaps ride 3 days then have a day off?

Many thanx.

Sally