Can't get it?
Don't sweat it;
let it come to you!
If it's right
and you hold tight,
your dreams will all come true!
You already know that worrying only fouls things up, but why? Because thoughts become things! And if your thoughts include doubt, it means you are able to visualize and see things happening in your life that you don't want to happen. And as soon as you can mentally see them, their reality (in the world of thoughts) emerges and they immediately begin striving to become part of your time-space life. And the more you think any thoughts, right or wrong, good or bad, especially when you feel them as you think them, the closer they get to becoming things.
So you set the stage for a battle when you also think thoughts contrary to whatever it is you want. And it'll be the thoughts you think and feel the most that you'll ultimately experience in the flesh. Although if you allow the battle to wage a long time, you may seem to get neither. Stagnation! Whereas, if all you think of are the things that you want, then their reality will literally come to you, because they'll be the only possible future you've created. It's so simple! You always get what you think about. That's how things work in this most amazing world of unending wonders. And when you really understand this, it will become very, very difficult for you to worry about, much less conceive of, a possible future containing undesirable things.
What's meant to be? Absolutely nothing, except for the reality, the future, that you choose to focus on. Think happy thoughts, and you are "meant" to have happiness. Think life is hard and it will be. Think thoughts of abundance, and you'll experience luxe! This isn't something that will start working once you believe in it; it's the law. It's how things already work in time and space, and it's the game you came here to master. So even when circumstances say, "No way," hold fast to your dreams and their occurrence will become inevitable.
Of course, beliefs, actions and words play a roll, too -- a powerful role. But at the end of the day, the thoughts you think the most -- which will inevitably be the ones you believe in and unavoidably move toward -- will become the things and events of your life.