Answer:
You have just engaged in counterfactual thinking.
Step-by-step explanation:
Counterfactual thinking is the human tendency to imagine possible outcomes for something that has already happened and which cannot be changed. It is counterfactual because it is different from what has already happened, it is "counter to facts"
In this case, you have engaged in this type of thinking since you are imagining and saying to yourself that you should've studied sooner in order to do better which is counterfactual to what actually occurred.