Necesito unahistoria en pasado continuo y en presente simple?

Yesterday I though it was a good idea start studying for my History exam.

So I took my book and sat in my favourite armchair, in front of the fireplace.

It was a very cold evening and I was sleepy.

I was trying to focus on the text, when suddenly I heard a noise.

At first I laughed thinking it was my dog, but I got really scared when I realised he was sleeping.

And then I heard it again.

But it felt so much closer now!

I could almost feel it : it was something trying to get into my house.

The door opened and I saw a huge shape walking very slowly to me.

My dog started to bark and run in circles, and I just didn't get it.

I was so scared that I could feel my heart beating, anytime was going out of my body.

The groan that thing did, really get me frightened.

Every second it was closer, and closer.

I closed my eyes and I knew that was the end.

Now I can only hear silence.

I open my eyes and I hardly see my dog sleeping again.

And I realised I alredy have the History book in my hands.

It was a horrible nightmare I had!

And now I'm sure I will never try to study again if I feel sleepy.