As an individualization of God, you already have the power within you to manifest anything you want in your life. What happens for most people is that they forget this fact and they begin to sink into fear about not having what they want in their life.
It is easy to do in our modern world, which is filled with distractions and lots of messages that say you have to have x, y, z before you can be happy, healthy and wealthy, but I know another secret.
You actually cannot have anything you want, as long as you are obsessing about it and are attached to the outcome. Your neediness of what you want is in direct conflict of the fact that you already have the power to create what you want in your life.
You are saying you do not believe in yourself when you behave like that. You are saying you do not trust in your own power of manifestation, and you reject who you are at the core, an individualization of God. When you can get in touch with your BEING power, and then take authentic action, you will have what you want. Only from detaching from the outcome can the source then bring it to you. It is that simple.