There's a few things you can do. Look into cleansing and protections specifically. Even if you're not cursed regular cleansings and protections can remove buildups of negative energy and prevent it from returning 5 seconds later.
You should also forget about the curse. Most curses are the result of the power of suggestion. [Your mom blames bad things on a curse which makes you believe it's a curse] everyone has rough patches, highs and lows are part of life. Accept 'bad luck' as simply a bump in the road. If every bad job interview, poor grade, and bad hair day is the result of a curse instead of a part of life, or personal growth, then you feed more negative energy into this curse. [Even if there wasn't one to begin with]
Also, salt is used to purify, not curse. While black has been used to curse, the colour has also been used in many positive ways as well. Black salt isn't evil as far as I'm aware.