Couch To 5K Week 2

Whew week 2 day 1 was a challenge.  This week is a brisk 5 minute warm up walk.  Alternate 1 ½ minute of jogging and 2 minutes of walking for a total of 21 minutes.  This time I started on the dirt path that goes up the minute and that seemed a little shorter then taking the paved walk.  When I got to the other end I went back on the paved path.  Still seems like I am going slower but the program says I am slowly getting better.  I didn't have much energy again.  I wonder how long it takes before you have more energy, it is easier to run and you can run longer without getting tired.  I wonder how long it takes to notice the difference in how you feel, look and how much you can run?