I could say it is just Karma, but would that really help? I doubt it. Black magic is not something for anyone to become involved in as you are finding out.
First thing to do is stop doing any and all forms of black magic. That means anything that involves demons, evil, hate, envy, revenge, etc.
Then start doing some of the cleansing and protection spells to rid you of any negativity and evil influences.
If you are keep doing them for long enough, you should be able to get the negativity and evil out.
Remember that any magic that tries to change the free will of another is really black magic, no matter what others call it. Casting even one spell of any type of black magic will bring all the evil influences back into your life.