Sometimes this can happen when you first start using The Secret and LOA. It can create a switchback effect in your emotions, but really what this is, is that your mind has doubts about your new thoughts. You are sending it new data and thoughts, but it had become so used to your previous down thoughts, that it thinks " Oh heck, I don't like this. This is change. This is different to what I'm used to. Best doubt this. Best go back to what it was. " And this is why you get the up and down feelings. But if you carry on with gentle persistence, your new thoughts and emotions will win out, and your feeling point will improve and stay that way.
When you are feeling down, it's like a football team which is off-form: it's a case of lose, lose, lose, lose, lose and so on. When you change your feelings, sometimes they go up and sometimes they go down, and sometimes they stay neutral, so it's like a football team which is inconsistent. It goes win, lose, win, draw, draw, lose, win, win, lose, draw, lose, draw, win, win and so on. When you have mastered your thoughts and feelings, it's like a football team which is really on-form: win, win, win, win, win all the time.