Because our thought process is constantly working, the Law of Attraction is constantly working as well. Many of our thoughts are at the unconscious level, so we're not always aware of what type of energy those thoughts may be creating.
According to the Law of Attraction, if you want something enough and you truly believe it's possible for you to have it, you'll most likely get it. But the same is true for negative thoughts.
If you spend a lot of time thinking on the things you don't want or fear, and you believe it's possible for you to experience them, it's just as likely they'll come your way. You can't avoid displeasing things by hoping they don't happen.
Your unconscious is literal and creates negative energy the same as it does positive energy. It doesn't know the difference. Your unconscious mind doesn't understand "I don't want". To truly achieve the positive benefits of the Law of Attraction, you have to become aware of what you're focusing your attention on.
Are you focusing on what you want? Or don't want? Do you have thoughts or beliefs that are opposite to what you want? If you truly want something, but feel you don't really deserve it, those thoughts will be translated into energy, and the Universe will go with how you "feel" that you don't deserve it.