Lost Worlds

I Was Using Minecraft Beta And Wanted To Leave So I Could Play With Some Friends.
but when looking up how to leave it, it told me to leave the program then uninstall Minecraft then reinstall it.
I left the program then uninstalled Minecraft. a day or 2 late I installed it back on my computer.
I opened Minecraft to go into my worlds but instead of seeing the list of all of my worlds it was empty.
asking me to join realms.
after thinking it was just a glitch, I exited Minecraft went back in and once again my worlds where gone.
I was wondering if there was a way to get my worlds back or if they are really gone.
( I am logged in to my account, I did reset my computer and I also tried finding the things I brought with mine coins but they were gone too. )