What you are vibrating is often different from what you're saying or "thinking". You can say all the positive things you want, affirmations in every sentence...but unless you've cleared the land (gotten rid of all the negative stuff in your belief system), the affirmations' effect will be minimal or if you see a result then it most likely will be temporary.
Your vibrations are based on your feelings. Although affirmations and positive thinking can give you a temporarily improved feeling so that you think you're doing everything correctly, reality is that you still have that underlying anxiety about the lack in your life. Why is that still there? Because you didn't identify your limiting beliefs and then work to clear them out, replacing them with new beliefs.
Every time you say an affirmation such as "I am prosperous and wealthy", your soul feels the contradiction between the words and the feeling "I don't deserve to be prosperous" or "all prosperous people are greedy" or "money is the root of all evil" etc. When there are these contradictory thoughts and feelings inside of you, your vibrations bounce back and forth like a ping pong ball. Nothing can come from that except more confusion and sensation of lack. You feel confused and clumsy and when saying the affirmations (or doing other types of positive thinking), you feel worse than before but you can't identify the reason. You're still stuck in the lack belief/vibration and that's what rules your results.
This is why so many people say that positive thinking or the Law of Attraction "doesn't work".
It will work but not by itself. You have to obey the other Universal laws and work on getting rid of your limiting beliefs.
Can you think of any situations where this has occurred in your life? Let us know by putting it in the comment box.