Possibly Possessed

@Demon6666666: Angel's(with a person's permission) can possess too, not just demon's and devils. Demon's were once angel's so it's no surprise.

I am an empath myself. I have seen a black mass before. It could have been my higher self but I call it an energy vampire. Now what it does is it absorbs the energy out of you. Of course, I am a person who can absorb energy around me too. What I had to do was absorb that black mass inside me, then ground it.

WhiteR4ven, I have to use chaos magick since more than 6 months. Also, I am always cautious about everything, and did not jump right into the advanced part of magick.
I use a protection sigil everytime I practice witchcraft.
...anyway, another reason why I think that this might be a possession is because our house is full of negative energy. My parents fight all the time and most of the times I am sad either of them or because my life is hard.
Now, combine these two together...
Also, I don't think that I am an empath for some reason...
I also now rethink about it, and I conclude that it might be a psychic attack from some enemies at school. The only thing that declares this possibility false is that I sometimes manage to overthrow the negative influence, but sometimes it struggles to torment me again.
Oh, what one of you guys mentioned about auras might also be correct. My root chakra is underactive while my crown is open.

P.S. something about the negative thoughts that occur: they used to happen most of the times I thought of the gods. Like it was trying to abstract me from them or something.

Anybody else?

For the more minor things wear a triquatra. If it's still an issue incorporate salt into everything you do... As salt is something demons can't stand it will probably chose to leave. And if that doesn't work get a cleansing.

And last resort, even after a cleansing get an exorcism.

If you feel all this to be to drastic, than attempt to either subjigate or befriend the demon.