Everybody is aware of the placebo effect. The mind has an amazing ability to cause the body to heal when we feel hope. When we feel positive about our situation, our body responds positively. It lowers stress hormones, releases endorphins, improves blood flow, and outlook. During a clinical trial, scientists don't want the placebo effect to influence the outcome, as they can't tell if it was the drug that helped or the mind that helped the patient improve her state of health. Yet, the powerful placebo effect remains. When there is hope in the mind, the body moves toward possibility. When there is no hope, the body feels and reacts to stress, raises cortisol, lowers the release of "feel good" chemicals, the cells become less responsive, and the body moves toward the physical response to no hope, which is disease. This is known as the nocebo effect, and is just as powerful as the placebo effect. When your doctor tells you your fertility status is dismal, he is only commenting on the ability of their drugs and procedures, not on the state of your own potential. When you internalize his prognosis, you give it validity. If you let the doctor's opinion remain his opinion, and move into how you actually feel inside, you can move from acceptance to a state of hope. Don't stifle "negative" emotions; let them be felt and released.
Energetically, when you feel hopeful, your body and mind vibrate at a higher level, which brings you toward higher potential. When you feel despair and resistance, your body/mind vibrate at a lower level where disease manifests. Yet, you can't merely talk your body into a higher vibratory level if every aspect of your being is not in alignment with the state of hope you wish you had.
The trick is this: instead of trying to convince your mind of what it wants, work at the level of the body. Experience the feeling of the state of hope you desire. Literally hold this state in your heart, and let it permeate every cell of your body. No need to focus on the image of your "goal". Just focus on the feeling of the desire held in your heart.