Ghost Of My Mum?

As by the title you can tell I'm even confused by this. I swear it was my mother. But even I think it cannot be possible. I told my mum the next day and she (like everyone) thinks it's impossible. As I do, but I saw what I saw.

My bed was length ways pushed against a wall I was laid on my side facing my open bedroom door opposite my bedroom door was my mum and dads bedroom which was also open. I'm not sure what time in the night it was but I opened my eyes (as if my mind told me to wake up to see this) to my mum standing in my doorway, I answered 'mum?' 'What's wrong?' she still stood there her face facing downwards her hair covering her face. But even weirder, wearing the dressing gown a specific tartan dressing gown that she wears. She does not sleep walk even though this sounds as if she does.

My voice started to panic I started to shout at her realising it wasn't my mum. I could see straight through her she was white typically 'as a ghost' I covered my eyes with the duvet, as I started to cry. Shouting go away! I had covered my eyes with the duvet about 3 times now looking carrying on shouting at her I looked and she had gone.

The next morning my brother said "why were you shouting last night, you woke me up" that's when I told the story where to this day everyone is still in disbelieve.

I am now 19 and still know what I saw and remember every part of it. My mother still says "how can it be me, I'm alive" which I understand completely.

My mother and me are very close; maybe she is my alive spirit guide? I don't no. I could understand if she were because we are so close.

Please help me understand this.