It's unlikely that your transient decrease in calorie intake had this effect on you (though it didn't do you any favors) unless it messed with your brain, which may or may not have happened.
I think the reality of the situation is you didn't provide enough stress from the previous workout where you missed reps to drive the adaptation to make the reps this time, perhaps coupled with the lack of food intake on your mental status when approaching relatively heavy weights. Moreover, since you had 1 week off previous to your last squat session where you missed, you don't have the accumulated fatigue to drive improvements in your strength. It's a training thing, not a food thing.
That being said, if you want to get strong- take care of your diet, don't miss days, and attack the fucking weights.