If you are surrounded by people who not only don't believe in your goals and your positive outlook on life, but who also continually try to tear you down, it will be extremely challenging for you to hold firmly in mind that you will succeed and that you can be happy.
There are instances when we are like horses, we psychologists, and grow restless: we see our own shadow wavering up and down before us. A psychologist must look away from himself in order to see anything at all.