Sounds like when you removed the substrate from your tank you removed it all at once and removed a lot of bb. Bb not only live inside your filters but a lot of it lives in the substrate. The white cloudy water is from a bacterial bloom and no amount of water change will fix it. You now have a cycling aquarium and it will take time for the bb to repopulate back to the level that it was before you removed the sand. Go light on feeding and keep a close eye on parameters for the next few weeks. You should be fine as your cycle didn’t fully crash.