Contacted By Spirits?

I don't know exactly when it began but I just have this feeling I am being followed! I turn around and see shadows out the corner of my eye, most of the time they are black but once or twice they have been white. I hear these random voices in my head and I don't know whether I'm imagining it or not. I try to contact these spirits but don't seem to get any replies or signs. I will now share two particular experiences with you:

This started about two weeks ago, I was in my room just about to go to bed, I went to the light just about to turn it off when I started to smell my dead nan! It was really scary and freaky because it just somehow smelt like her, I could especially smell smoke because she used to smoke. I have never smelt someone who I knew was dead before and I don't know why I smelt her, I just knew it was her. Do you think she was near me, trying to contact me or something?

The second experience happened today I was in form this morning when I suddenly heard this voice in my head saying "meet me by the tree at five, five past one". Well at least I think that's what it said. I don't know whether I imagined this up or changed it or I was actually contact, I'm not really sure.

But just a minute before five past one I turned around and thought I saw a black shadow out of my eye, although it was not that clear. I had been seeing shadows around that area the past week or two and most of the time they are quite faded and I don't know why. My school used to be a hospital so I think there might be some restless spirits there or something, I have tried to do some research but haven't found much.

As soon as I saw the shadow I looked at my watch and noticed it was almost five past one so I rushed down to 'the tree', I don't know how I knew what it meant, but 'the tree' is the tree me and my friends sometimes meet up by. As I was about ten metres from the tree it looked like there was a black eye on it but as I got closer I just noticed it was holes in the tree. I walked around but didn't see or hear anything.

What was this, did I just imagine everything or was I actually being contacted by a spirit? If you can help on any of this please post a comment! Thank you.