I wish I had better picture of my process, but I didn't think it would turn out this well so I just went with what I had. I still want to share it, though, I really like it, I just have to figure out how I want to put on a handle!
It is basically 5 squares the same size with the brown border on the top of two opposite sides and they are sewed into a big cube with no top. Then I pinched the sides and sewed the inside of the top of the sides so they would stay pinched in.
I sewed velcro on the top to close.
[The bottom is blue!]
And my make up isn't overflowing anymore!