*Spoilers* Is there a way to go back before the Tree of Life event?

In Dragon Quest 11, there's a huge event, where:

most of the world is destroyed.

I had 3 quests that were still in progress, but after the event my quest log has changed and they seem to now be gone.

Did I just miss on those quests, or will I be able to complete them later?

PS: If you could keep the answers as spoiler free as possible, I just got to the tree of life cutscene

(just got passed the part where you are a fish).

Don't forget the 'spoiler' tag if you want to explain stuff!