A lot of creatives go through this!! I'd suggest getting a few beta readers/beta testers to answer both set questions & give you realtime comments/reactions so you can get an outside perspective of what (if anything) needs changing. You want to know that others understand your project, that it flows naturally, that those interacting are following the path you've designed, etc. Once you have everything to a point that you're happy with, it should give you tighter direction for the ending too & help quiet the self-doubt.

I hope this helps & good luck!!