Scanned through the posts and if you are just starting out, I would disagree with those who suggest adding riding on the weekend. When I first started my 15 mil RT commute, I would gradually wear down over the week and would need the weekend to recover. I remember strong "Monday legs." Fridays were pitiful.

After a few years of doing that on a hybrid, I was in better shape, bought a road bike, and soon the commute felt too short and too easy. Took about 3-6 months of group riding to get to where I could hang without suffering.

I now try to ride at least 100 miles per week, but am fine going 150 or 200 miles per week. Did a ride of 70 miles of last weekend and would have been happy doing another 70 if it weren't for the rest of my life interferring with riding.

It will come. Make sure your bike fits and, if you are riding every day to work, take the weekends off this year.