SHAKE and then STIR

Sometimes things should not only be stirred but shaken good and strong. 

I am happy to say that I'm back in writing mode. The only thing that's not making me happy, or rather is confusing me is the telling of this particular story.
I am a linear writer. I write in sequence, page by page, chapter by chapter. It has worked for my 3 manuscripts so far, making up almost 600,000 words in total. It is not working for LUHU, this  particular story. Is it because LUHU differs from the other 3 in narration? Is it because I'm using 1st person POV for the very first time? Is that why I find LUHU a hard story to sink my bones into? 
If I'm only writing from the heroine's point of view, I'm limiting the story to her and her understanding of the world and events. Or is it because this story is different from my usual happy tales of romance and myth? It's almost a tragedy...almost...and I am first and foremost a happy writer. A happy person too. 
But I want to write this particular story...have to write LUHU how I've imagined it. Surprisingly, the heroine of LUHU must learnt to step out of her comfort zone too. 

So, wish me luck on this endeavor, Good Readers. And I will wish you all a good day :)