So since the beginning of July I have started making houses in a 1.17.1 flat minecraft world. I use Lunar Client for everything in 1.8.9. So I was just playing bedwars and decided to see if I could just finish my house in 1.8.9 and i joined the world but left because it wasnt loading. I then went to my regular minecraft optifine 1.17.1 launcher and opened it then joined my world and i was under water in the ocean. my world wasnt flat anymore and all my progress was gone, i dont know what to do. i spent several hours on my houses and i was just currently making one earlier today. please help if u can