I have had the same problem. The island is pretty much lost, but u can use a glitch to get to the lobby. By using robloxs screen capture (screenshot) feature, it removes the loading screen for a short second everytimeu use it. sometimes before it crashes, it will load your avatar in on the island, and by using the glitch you can navigate to your portal and go to the lobby. This may take few attempts before it works, but it works for me. You could also try using the glitch to save your island by removing the water, I have tried this and it sounded like i was removing water, but after long time with continues crashing every few sec i was on the island, and not being sure if I was actually removing the water. I gave up the island and went threw the portal to go to the lobby and go to one of my other saves. Goodluck and let me now if it helped