Don't "THEY" say (whoever "THEY" are) that you should only increase the distance of your rides by 10% at a time?

Personally, I think if you are going to place these demands on your body, you need to make sure you build in recovery - so days off the bike is recovery... but you can also do "active recovery" which may still be commuting to work, but at much less intensity than usual so your HR stays in "Zone 1 and 2" - that is, where you can talk or sing comfortably, so it is raised hardly any more than if you were walking.

If you are commuting you are doing two rides a day - make sure you fuel yourself well, and I don't know what your work involves but make sure you are resting during the day (eg, feet up during lunch, or even lying on the floor)