Need HELP looking for a manga

I havent read it but it wasnt rly long and i think it was either shounen/shoujo/josei.. anyway so the main guy gets stuck inside a manga he himself made and meets the heroine (long dark hair i think) there and develops feelings for her (maybe) or just starts caring towards her ,but since he wrote the manga so he knows her fate and it aint good , so hes stuck in a dilemma ... Can anyone help im dying here ┗( T﹏T )┛