Guardian Gone Bad?

I've had many different paranormal experiences, ever since I was a small child; I've experienced many different things. But for this story, I'm going to talk about the one in my room.

A long time ago, my Aunty died from cancer. Her husband, my uncle, died a few years later from cancer also. It was a sad time for my family as they were so close together. When I was thirteen, I got hit with a pretty serious illness. I had severe abdominal pain and after my surgery, when I came home I noticed this presence in my room. It'd always stand in the corner of my room, even during the day I sensed its presence, but I usually sensed it when I went to bed. I couldn't quite put my finger on it, but I felt like my Aunty. But other times, it felt like my Uncle. I think they alternated, if spirits do that.

When I felt it watching me, I didn't feel tense or threatened like I usually do, I felt safe when it was around. Sometimes, they'd say hello to me or call my name when I was lying in bed, this was rare however. They left after I got better, I didn't see them for another few years, nor did I sense any malevolent presences. But, then I got depressed. It was pretty severe as well; I had it for almost a year. When I had it, I felt them watching over me from the corner of the room again. But this time, they went one step further; they'd comfort me by stroking my hair and projected this safe presence onto me even more. In a way, this helped me with my depression a little. But one day, they were simply gone, I gotten over most of my depression, although a little was still there. I found this odd because I thought they'd see me through this to the end with me. I didn't think much of it at the time because I had other things on my mind. But sometime last year, the spirit in the corner of the room came back. But it was different this time, the whole demeanor of this spirit changed. I felt like it threatened me. This spirit would also follow me around the house and the one before didn't do this. I feel it glaring at me when I would sleep. I sometimes feel its icy cold breath on me and its cold hand brush my shoulder.

I just don't understand, but this spirit would stand in the same corner as the previous one did. So did it change? Did it get corrupted by some demonic force? Any input you have on this would be greatly appreciated.