maybe you could either take a little break from reading and go do things entirely unrelated (preferably not sad, like dont go watch a sad movie) or if you want to keep reading try a completely different genre than the book that broke you (so if the book was a romance, read a mystery next) ♥︎ hope this helps
I mostly read a happy romance book (might have some smut in it) whenever I finish a sad book. or I just watch happy movies to keep my mind off the book
Hint: the book is A thousand Boy kisses