Transmigrated as Dead Heroine

I was doing well before my birthday started when I suddenly fainted and lost consciousness for days and during that time, I realized something funny. I transmigrated into the body of the dead heroine! Of all the characters I could possess why does it have to be the unlucky heroine?! To top it all, she even signed up for her demise at a young age. "glad you woke up, Wren. You made us worry." Caesar the unpredictable brother of mine hugged me and let out a relieving sigh while I was planning my survival here. God hates me somehow. I should be celebrating because I finally experienced transmigrating into a book I know, but I can't! "Fainting in the middle of the banquet is unsightly." if I can wish for a new father, someone please grant it immediately. I possessed the body of the heroine... But... DAMN IT! If I will be transmigrated in a book, please I will be glad if I become the extra or side character as long as it will guarantee that I will live long! "I hate girls like you. I still remember the way you ordered me around to marry you." He's looking at me like he will kill me if I don't go away. Unfortunately, that happened before I had known that he's going to be the one who killed me. The heroine will die at the hands of the Male lead, her betrothed. I know this is unusual. A heroine dying at the hands of the male lead... this is... haah. Nothing will change even if I whine here since I am Wren. I did everything I could to turn everything the way I wanted and it did. Except there's one problem after another. I found out that something changed about the male lead and not only him, everyone around me is acting different which makes it more annoying! I think I changed everything so much that it became annoying.