I can’t use the original texture pack

I recently updated my Minecraft app, and when I entered one of my worlds, I noticed that the textures were different.  I hated it.  I tried searching the Minecraft store to see if the original texture pack was available.  It was not.  What was available was a texture pack called Minecraft texture update beta, which looked exactly like the ugly texture pack that was applied to my world.  I tried downloading it and turning it on.  When I entered my world, it  looked exactly the same.  I then tried turning it off and entering my world again.  No difference. I tried it on my other worlds, it does the same thing.   I tried looking this up, and from what I can tell, nobody else has so much as mentioned having a different texture pack in their Minecraft game, which leads me to believe this isn’t supposed to happen.  Please look into fixing this glitch.  I really hate the way my worlds look and I’d like to use the original texture pack.  Thank you.