when i was younger, i would run 100km/week ... now, I barely ride that due to time issues
however, the first lesson I learned was that "rest days" were actually much more important than "training days."
for long-term progress (over a time-scale of at least one year) the rest days are essential to prevent burn out.
think about it this way, you've shaved roughly 20% of your body weight off, and wonder why your legs are tired?
rest.
i'd just start riding every other day and start converting the rest days back to training days when your legs don't feel like lead pipes anymore.