Astral projection to visit a ghost?

My sister lives in a haunted house. More on this later. She believes there are three ghosts in the house: a young child (rarely encountered), an old man (benevolent) and a 30-ish year old woman (malevolent). The woman terrifies my sister and her children on a regular basis. My sister can see her/picture her; she tells me she has long dark hair, and does not like to show her face.

My sister lives several states away from me. She was going through a rough time when the activity in her house was really amplifying, and it was freaking her and her children out. We talked on the phone 2-3 times a week, especially about the house.

Let me mention that I do not like my sister's house. I spent a night there about a year after she moved in. She believed that the house was haunted from the first time she entered it, but she didn't tell anybody until the activity started picking up more and more. The one night I spent there, I had a really hard time falling asleep, and felt like I was being watched, no matter what room I was in. Only later did she tell me it was haunted.

Anyway, at that time, she was constantly telling me all the scary stuff that was happening in her house. I felt compelled to help her. I talked to a few friends of mine: a Wiccan who had advice about spells of protection, and another spiritually-minded friend who said my sister shouldn't live in a house where she felt terrorized: she should try and take control of the house from the ghost, or if not, she should move it.

My Wiccan friend explained in great detail to me how to cleanse a house and set up a spell of protection. I also read up a bit about it on the internet. I was going to visit my sister and started planning a good evening of cleansing. I purchased many supplies: white candles, incense, smudge sticks, etc. I went over the cleansing ritual in my mind over and over (burning sage counter clockwise as you move through the house, etc.).

But then, once I got there, my sister said, she wouldn't let me try it. She was too scared that I would make something worse (she had had other ghost hunters out who had smudged the house, and she felt it suppressed the good spirits and allowed the scary female spirit to grow stronger). I was very very frustrated with her. We had spoken of this issue over several months and I had invested a lot of time and money in prepping for this, but she wouldn't let me carry it out.

Let me also say my sister is one of the bossiest people on the planet. You cant talk her into anything she doesn't want to do. This caused me a lot of frustration and anxiety - mostly that she wouldn't help herself, just stayed a helpless victim in this house.

So, then, one night, I dreamt I was in the house. There are two places in the house where the female spirit hangs out the most - in my nephew's closet upstairs and in the basement by the water heater. First I was in my nephew's closet. Looking back, it seemed that I was floating, or I wasn't really aware of my body or anything like that. I looked in the closet, poked around, searching, searching, searching for the spirit. Then, I decided to look in the basement. I went down to the water heater. My sister is a bit scared of this area now - she thinks the ghost lurks behind the water heater, so she rigged a cloth curtain she sewed from a sheet around it. In my dream I pulled back the sheet and stuck my face up next to the water heater, peering in, peering in, peering in, was she down here?

Suddenly, something flew at me in a rage. I could almost hear a screaming (non-human screeching) inside my head. The light went from white to brownish and then it felt like I was smacked in the face, two, three, four times. It didn't hurt at all, it just felt like hands slapping me, pushing me back, and I felt a very clear message, "GET OUT OF HERE."

Many months later I asked a medium about this (a friend of one of my friends). I told her about my sister's house, she went into a brief trance, and then she said, "I don't want to scare you" (and instantly I felt goose bumps) "...but I think this female ghost is dangerous."

When I told her about my dream, I told her I felt that it wasn't just a dream about this spirit, that it felt very real, and very physical. She said she believed I was actually there, that I had traveled to the house in my dream and had a real physical encounter with my sister's ghost.

I was very frightened but also mad. I had made no conscious decision to visit this spirit (if indeed I had), and realized that maybe I was way too invested in my sister and her own ghost story. I couldn't fix this for her. If this had indeed happened once, it could happen again without my choosing. Thankfully, it hasn't.