Imaginary Friends

I wonder if anyone would be able to give me some advice on my story. I am unsure if it's real or subject to an overactive imagination.

Roughly at the age of 3, I began speaking to 2 imaginary friends. I am now 20, but I remember these friends as clear as day, looks, clothes and personality. I called them by names, Stevie and Marlin; my family knew nobody with these names. I remember having discussions with them and even setting my Granny's home on fire because Stevie asked me too.

I remember the last time I spoke to them, I was around 5. My Father was sitting on the chair in the corner and my mother on the other side, I was speaking to them and Stevie was sitting on top of a speaker (attached to the Hi-Fi) My father turned to my mother and said that he was concerned and I had to stop speaking to thin air. I told them I couldn't speak to them anymore and never spoke to them again.

I experience Déjà-Vu all the time, and experience very strange dreams.

Roughly around 3 years ago, my cat passed away. I had nightmares for 2 nights and on the third night I was watching television and I am around 95% sure I saw my cat sitting in front of the bed this appeared for roughly 5 seconds before I blinked and it disappeared. I presumed this was my eyes playing tricks on me, but I am unsure.

Three nights ago, I was walking up an ally way in the streets of old Edinburgh, and I heard footsteps behind me, I turned around and nobody was there, I carried on walking and the footsteps continued behind me, I became cold and teary and goose bumps appeared, I turned around and again nobody was there. I hurried up the path and I felt fine after this.

Please give me advice.

Thanks