Please analyse my game

15...Nh5 idea is sacrifice on g3 ( Bxg3) that was idea
what was the best continuation afther 18.Nxg4 since ...h6 looks like my hugh weakness and its hard to find active game afther 18.Nxg4
I can try something like ...Rfc8 with idea of ...Nb4 and freeing nice square for bishop (f8) positional understanding demand that move...but question is did I have enough time for all that? Really ...h6 is hugh weakness and looks like not possible to solve
This is my game from 3rd round of Croatian 3rd League.
Where did I went wrong?
Is ...h6 lost tempo and own weakness?
Was possible sacrifice bishop for 3 pawns?
Did I have defense afther opponent's sacrifice on h6?
Was ...f5 mistake?
Thank you in advance