Skins show in launcher and on official minecraft website, but not in game.

So as in the title, I'm having a skin glitch. My online profile says my skin is a shark:

SkinWeb

And so does the launcher:

LauncherSkin

But when I click play and join a regular world:

I go back into the launcher:

BackInLauncher

In advance, I thank you for any help because it would mean a lot if I could see any type of skins other than defaut ones.