I was around 14 when this started and 18 when it ended. It's rather uncomfortable, so bear with me on this.
When I was 14 or so, my dad started looking at me in a way I didn't like. Anytime I was in the same room as him, he was staring like I was, well, not his daughter. I spent a lot of time outside reading or hiking just to be away from him. He was kind of a gross guy, and didn't care whether he used his toothbrush or mine or Mom's. Toothbrushes are sacred, and as we didn't want our toothbrushes violated, Mom and I started brushing our teeth and keeping our toothbrushes in the kitchen. I still brush my teeth in the kitchen to this day. Old habits are hard to break. I also developed horrible insomnia around this time. Dad was a heavy smoker, and his breathing was loud and wheezy. Not a pleasant sound.
One night while brushing my teeth I heard Dad's breathing behind me. I froze, afraid that he was going to try something. I turned around (better to face a threat head-on) and no one was there. I chalked it up to my mind playing tricks on me. Sleeplessness will do that after all. This became a nightly occurrence. Me brushing my teeth while the breathing kept on behind me. Dad was almost always in another room, only once or twice was the breathing actually him. Now, at this time, my father worked out of town for 2 weeks at a time, and had one week off. I slept some while he was gone, but even the 2 weeks he was gone, the breathing continued. And when he was home, he stared. This is where things get truly uncomfortable.
One day when I was 16, he was on his days off. I was sitting in the living room, when he called me into his room. Being an obedient moron, I went. He tried to molest me. I got away and ran as fast as I could into the woods, to my favorite place by the creek. Eventually I moved from the creek to an area that allowed me to see the house, but no-one from the house could see me. I hid in the woods until Mom got home from work, and told her. She of course was furious for the rest of the day, and then it was swept under the rug and forgotten. The staring stopped for a little while, but the breathing incidents got worse. I was thrilled when school started back up, less time at home. I started hanging out with one of the teachers after school. It was a church school, and this teacher was a very genuine Christian, she truly walked the talk. I considered telling her, but couldn't bring myself to. Mostly I just went to craft stores with her, and then camped out at the library until dark. Then home.
He'd started staring again and the breathing seemed to get heavier and wheezier every night. I started hearing it outside my bedroom. I couldn't be sure if it was Dad out there, or just that disembodied breathing. It all finally stopped when I was 18, and lost my virginity. It was like he knew, he stopped staring, and if he looked at me at all it was with disgust. The breathing stopped too.
After considering this for many years, I've got 2 possible theories on the breathing. One, it was a manifestation of what dad wanted to do. Two, it was a manifestation of my fear. I'm curious as to what others may think this was. Also, writing this out was a kind of therapy, so thank you for reading this.
I've come to the conclusion it was a poltergeist. There was plenty of tension to feed that sort of manifestation.