World Seed Corruption

So I started a new world on 1.16.3 and it was originally from 1.19.1. I loaded in n 1.16 to see that the seed has changed, and there was a shipwreck at spawn. I made some progress and was testing stuff out on my new resource pack and then loaded on 1.8.9 to play a server with my friend. I accidentally clicked single player and loaded that world but it wouldn't let me cancel so it ended up loading. Before I spawned in fully, I quit and 5 minutes ago I joined on 1.19.2 only to see that the shipwreck and my base were gone. I still had my tools and I  was like "oh I could just get the world seed and remake it" but I typed /seed and it replied with "Seed: [0]." I tried again. Same thing. Can anyone help me restore the seed? It wont let me send over the world because the file size is 17MB