Short story about a girl who thinks she hears something strange coming from her mirror.

I woke up to hearing a knock on the window, until I realized it was coming from the mirror. I stayed in my bed. Eyes wide open, my heart racing I can feel it in my throat. I try to ignore it pulling the covers over my head, but there’s another knock. A light knock with the fingertips. I turn on my light and took a panorama with my head. Difficulty to swallow, hands shaking, legs stiffen, I stare at my reflection. I hesitantly knock back to the mirror. But nothing. I proceed to look around the mirror as if I’m looking for something seeing the reflection of my room. After minutes of searching around my room with my eyes unsure of what I’m looking for, I check the time 2:33am. Trying to calm myself down, I head towards the kitchen to grab something to drink. Suddenly, I hear shuffling around coming from my room. Really confused and worried,  I quickly speed walk towards my room to see what was going on. Again nothing. Everything was how it was before. Still shaken up, I decide to go back to sleep. I check my phone for any notifications to keep my mind off of the strange events. The time was still 2:33am.
“Strange” I said to myself. Putting on some netflix my heart slows down and I fall asleep. Right as I’m about to fall into deep sleep. Three loud bangs with the screeches of nails on a chalkboard scream from my mirror. My eyes widen, bungling from my eye sockets, I scream and can feel my heart in my knees. I quickly turn on my light again. Written all over my mirror with a deep, dark red was
‘I’m Here.’
Suddenly my alarm is blaring. With disbelief, I get up and turn off the alarm. I can feel my head pounding and my sweaty body. I sigh in relief realizing it was just a dream. I turn on my light to see in a deep, dark red,
‘I’m Here.’