My underwear problem

Note: this is fiction (ça c'est ma partie favorite...)

One morning I woke up. I was very stressed: today was my final exam of math. I went down to eat my breakfast then I brushed my teeth. I opened my top-secret drawer where my good-luck underwear were supposed to be.
-"NO!!!" I yelled "Where did I put them?"
-"Mom, Dad have you seen my good-luck underwear, they're white with exactly 101 red hearts?"
-"No. I haven't seen them sweetheart" said my mom "maybe the dog took them."

I was desperate: in less than 30 minutes the test would start. I looked everywhere: in the refrigerator, in the dog house and even in the garbage bin...
-"In 25 five minutes we have to go" said my mom.
Okay, no time to lose.
What if I invent a robot that can find my lucky underwear!
-"I can sell you my electronic workbench but it doesn't come cheap!" said my brother.
I had no choice: -"Okay, how much does it cost?"
-"2000 pesos" said my brother.
-"What!!!"
-"I told you it doesn't come cheap, but you know it's your choice, it would be a shame to lose those underwear..."

So I paid 2000 pesos and all I had left was one miserable peso standing alone in my piggy bank! Quickly I went to my brother's workshop. BZZ, ZZZ, FZZ, LZZ! I put anything I could find together. Finally the perfect underwear detector was born! It was not very elegant but I had no time to care about the look. I wrote my school address and drew a picture of my underwear. I pressed the activate program.
-"Sweetheart, we're leaving in 2 minutes" yelled my mom.
Rapidly I took any pair of underwear and put it on.

I had to start my test without my lucky underwear. !0 minutes after, there was a knock on the door.
-"Come in" said my teacher.
The humiliation....There was my robot, proudly holding my lucky underwear in front of the whole class.
-"Hello C., I found the underwear you lost!"
My friends burst out laughing and I thought I would die of embarrassment. However the worst was yet to come...

The teacher refused to let me go to the bathroom...So to get good luck, I had to wear them on my head.

What a day!