My first thought is that you haven't been back to riding that long- just a month so far. It may be that instead of easing back into cycling, you just jumped in full on. Perhaps you just need to ease back the mileage a bit and slowly add the mileage back on over time. The rule of thumb is add only 10% additional to your workout per week. So, for instance, if you start by doing 10 miles a day, 5 days a week the first week, the next week, you can add 10% more effort on, so you'd increase from 10 miles to 11 miles a day the next week. Then the next week, you can go 12.2 miles... and so on and so on. When you have built up a sufficient amount of mileage, you can start adding in those longer days where you do lots of mileage, and vary it with other days, where you do less mileage.
I think you have plenty of recovery time- 2 days off is a nice amount of time off, provided that you are doing nothing more than an easy spin with low mileage to keep your legs fresh.
What are you training for? What is your schedule exactly from day to day? I think if we had a better idea of what you were doing, we could be a little more specific with our responses. 10- 40 miles a day is a bit of variety!
I'll wait to hear back from you.
Koff