Have you ever done 10 reps of an exercise and stopped because your plan said you were done? Have you ever eaten the last 300 calories in your eating plan to fill the number, even though you were full? Every day is different. Some days you'll be firing on all cylinders, others you'll be dragging your feet. One day you may be ravenously hungry, and the next, perfectly satisfied. This is completely normal. In my opinion, getting the most out of every day requires being flexible, and listening to your brain and body. If you're flying high then let yourself take off, get those extra reps in, go that one step further, because... why not? I can't stress the importance of having a plan in place, to give you guidelines to work within - but there is no reason to let that restrict you. Of course, this works both ways. If you're not feeling yourself, wrap things up and fill that need... Whether that be cutting your session short because you need some rest, eating more/less than you're plan because you do/don't need it that day, or whatever else it may be. Take it one day at a time, and don't pressure yourself to feel a certain way - rather work with how you feel on a given day.