I changed my account on my computer and then put Minecraft on it, using the same account I have always used for Minecraft, and when I launched Minecraft, everything was gone. My single player worlds, my multiplayer servers, my texture packs, everything. I have already looked all over the internet for help and went into my Minecraft saves folder but it was empty. I think everything is gone for good but I really can't deal with that because I worked super hard for years to build and create everything I had. there has to be a way to get it all back.