What do you do when you're upset over something that's your own damn fault?

Accidentally left my vanity case in reach of my sister's 3 year old son.
Came to the bathroom to find half of its contents in the shower, and three of my nice makeup brushes ruined.

Now I gotta save up for a bunch of new makeup, because OF COURSE my essentials were on top and got annihilated first.

I know it's a stupid thing to be upset about, but damn it that cost a lot of money.