About to make a very stupid decision

The most important exam of my life, my medical college entrance exams, are now 9 days away. And I've prepared as much as I can, and am getting decent scores. I'm also pretty burnt out and can feel my brain giving out in the middle of mock exams this week.

So I've decided to just absolutely waste time tomorrow. After my morning exam, I'm gonna go to a restaurant nearby, without telling my parents much, and use the money I keep hidden for emergency purposes. And maybe stop at the closest cheap chain confectionery store branch and buy myself a mid tier brownie. (I'm pretty sure I'm exhausting all my leftover money in just the restaurant tomorrow)

Is this a stupid idea, should I get straight back home and continue studying or execute this plan instead?

(posting this at 4am btw. I'll check in the morning, if the majority consensus says I should go for it, I will fr)