Negative thoughts can be tricky to deal with, especially if you want to stop attracting a specific one, but you can use counter-thoughts to easily manage negative thoughts. Counter-thoughts are essentially the opposite of negative thoughts in that they are entirely positive rather than negative.
For instance, if you think a negative thought about your health, you can then counter that negative thought by generating a new thought that is positive and about good health while also allowing yourself to focus upon this new thought in the same way you focused on the original negative thought, in a way that triggers strong positive emotion within you. By doing so, the negative vibrations and the attraction of negative thoughts will be diminished and replaced by positive good feeling vibrations conducive to good health and the attraction of more positive thoughts will thereby result.
You can do this with any negative thought too. The trick to using this process is the allowing of yourself to give your attention to a positive thought just as you allowed yourself to give your attention to the original negative thought. It is common for people to simply think a negative thought and dwell upon it while experiencing the corresponding negative bad feeling vibrations. By using this process instead though, you will be able to instantly switch your focus away from the negative thoughts you come across and replace them by focusing upon positive thoughts that will create much more desirable experiences for you.