Same workout- different effects from day to day...possible?

I am very confused. I am doing NROL4W, my workouts are M,W, and F. I missed Monday so I made up for it today. I know my typical calories burned during my workout are around 200-240. I was not in a very good mood today and did the workout...same reps same sets and only burned 145 cals (heart rate monitor). Is this possible? Does anyone have any words of wisdom? Can mood affect your workout like that?

Thanks!

 Mood affects intensity, intensity affects how many calories you burn. If you're not in the mood to push yourself, you won't work as hard ;)

Thank you! I appreciate the feedback. Maybe I am not as nuts as I thought.