Is it a mouse or rat?

There's a rat somewhere in my house,
Or maybe its a mouse,
I'm not really sure how to check,
But I'm afraid it will bite my neck,
Oh are vampire rodents real?
Can my mortality it steal?
Its one O'Clock at night,
And here I fret over a vampire rats bite,
That's it child, no more Twilight,
But imagine if the rat crawled into my room,
Dressed like a zombie groom,
Oh what would I do?
I have nothing borrowed nor nothing blue,
Oh midterms how I hate thee,
Look what you've done to me.