That sounds like me. I was too attached to the idea of testing IM to see whether it was real or not that it contaminated all my intentions with this intention.
More info here:
Mind-Manual » Life/Happiness/Intention-Manifestation Tip
and at the Quantum Leap link in my sig. Another thing that I mentioned in the thread ALG posted is to focus on what you really want, decide on it and do it regardless of whether you get IM-magical help or not. Just have to tell yourself that you'll be ok even if IM doesn't work and is just a load of baloney cause its simply one thing in a process of exploration and growth that is your life. If this thing doesn't work, the next thing you try just might.
Manifestation comes in many forms, including direct action, magical action, synchronsity, etc, don't focus on limiting it to just one way of manifestation. Allow it to manifest from different ways. And if the method presented to you is too difficult or complicated, ask for a simpler method.