i lost my shit - When you see or hear something so stupid or terrifying that

When you see or hear something so stupid or terrifying that you can't help but laugh or scream so hard you poop your pants.

My dog ate my homework and I saw the mess he made. I lost my shit.

The teacher yelled at me for talking during the test. I lost my shit.

I saw my little brother wearing my mom's underwear. I lost my shit.