Help with fixing a nightmare?

I'm writing the beginning of a story about a girl who is turned into a werewolf. The whole story ends up being psychological horror, mixed with some good old, buckets-o-blood slasher elements.

The main character has just been gruesomely attacked by a werewolf. The only thing that saved her life was the sun rising. For my werewolves, the only way to be turned is to survive a full-moon attack long enough for the sun to rise. Your wounds heal, and BAM. There you are, a freaky man-beast with the consciousness of a demon-esque wolf inside your head.

Anyway. As I said, the main character has just been attacked. She's already a little off-balance, so when she eventually falls asleep, she has a nightmare. I like the content itself, but I can't seem to make it flow properly. Could you read it and tell me what's wrong? Because I can't put my finger on it. Please, don't rewrite the entire thing for me, because I'm not interested in using someone else's work. Just tell me what you think is wrong with it. Thanks :)

I fall asleep by nine. My dreams are chaotic, filled with short punches of roaring static and a frantic drumbeat like a panicked heart. Vines with thorns like claws pin me to the trunk of a great tree whose branches clutch desperately at the sky.

I thrash in darkness punctuated by blinding moonlight, and when I open my mouth to scream, a howl rips past my lips. The sound is cut off with a gurgle as blood rushes up my throat. It fountains out in a glittering arc, staining the black leaves and silver moon with scarlet. My jaws stretch wide as the blood gushes through, popping and groaning, and rivers of it slide down my naked skin. Pressure builds in my stomach, and I feel like I'm about to burst like a bloated tick.

Then a slick limb thrusts up from my throat, glistening and pulsing in the red-stained light. Horror freezes me as a dark form drags itself out of my belly, splitting my jaw in two. There is a deafening, fatal crack as its head emerges, and the moment before I am torn apart, I see a vicious yellow eye glaring at me with all the evil of hell in its depths.

MINE.

I jerk awake. Black fog fills my head, and my ears echo with howling. Screams rise in my throat as the howls rise, becoming shrieks of rage and excitement. I clutch my head in my hands, nails digging into my temples.

MINEMINEMINEMINEMINEMINE--

“Stop it!” I scream. The noise chokes off with a yelp, and I am left alone in my room, fresh scars glowing like bloody rivers down my skin.