back to the grind!

I have been very bad the past two weeks, just stressed with papers and clinicals and all the stuff that goes with nursing school. Working out was completely thrown out.... not even on the back burner. Healthy eating slipped a bit. But, as of yesterday, I am back on the exercise and already feel my body kicking in! After work yesterday, I did 3 miles at 4 mph/3.5 incline, 3 sets of 20 thigh burning curls with 11.4 kg weights. Today, after class, I did 3+ miles at 4.3 mph/5 incline. I find that holding my stomach in and clenching the bootie makes for more soreness (i.e. is more effective) than regular walking. No time for machines or tension bands though, but I felt it was sufficient. Why has everyone fallen off the wagon?