You focus on being bigger than your problems.
In life.
In love.
In business.
In general.
You don't worry about things as much when you realise that everything is figureoutable (< is SO a word).
As you expand in any area of your life, you're going to be presented with 'are you sure you really want this?' challenges. And if you can't handle the small shit then you're not going to get an opportunity to grow into the big stuff - which is where everything you say you want is hanging out waiting for you.
Sometimes you have to step away for a bit to get some space so you can reframe your 'problem' and realign your perspective. Then breathe deep into every corner of your solar plexus to activate your confidence and authority before you start figuring it all out.
You can manage your stress and get perspective quickly when you double check to make sure you're not gearing up to climb the tallest mountain when it's a little ant hill sized problem.
The key is to realise that your brain is trying to keep you safe so it MAY just be messing with you by convincing you that your problems are bigger than they really are. Your brain's main job is to keep you alive so sometimes it's like an overprotective fusspot Momma. When you reassure yourself that you're in control and that you're confident that you've got this then your brain is going to get on board to help you make it happen.
The problem most people have is they're relying on their brain to lead the way but your brain is wired for survival, not success - so YOU need to take the reins confidently to get your brain on board.