Seeing dead people: hallucinations or clairvoyance. Am I right, or am I right?

Two weeks ago I saw the old lady that usually smokes on her balcony.

She lives in the same area as me and I see her frequently out on her balcony smoking with her husband. I was on my way home from school. Exiting the forest, I glanced in her direction. I thought nothing of it at the time, since it was quite common to see her there. A week later, I'm speaking with my mother and she tells me that the lady has been dead and cremated for three months.

I saw her as I saw my own reflection. When I told my mother about this, she gave me a smile and told me it's because I "have an open heart". What the hell does that mean?? I'm most probably loosing my mind, and she's telling me that I have an open heart? I would rather be accused of insanity and be lobotomised. 

I am not a stranger to the paranormal. My belief in it dips from time to time, but I would say I mostly believe it. I've experienced plenty of unexplainable things, ranging from hearing people that aren't there, to seeing shadow people. This week I heard chanting outside my window even though I live on the second floor of my apartment complex. I've seen what my mother calls "the boy", heard my sister calling for help when she wasn't home. I feel presences in empty rooms. 

This isn't my first time seeing dead folk, and if my life continues this way, it certainly won't be my last. Strange dreams and seeing things is all laughs and giggles, but if someone has an explanation to my issue it would be greatly appreciated. I will say that I have no experiences with psychosis, and I am not diagnosed with anything that can cause hallucinations.