Healthy dose of fear is good. It helps you from abruptly abandoning good commitments you’ve made and invested time in. But, there is no point in living in constant fear. If there is something bothering you – put the damn work in and solve it.
And if there is something you can’t solve it no matter how much effort you put in – accept it. Don’t whine and complain about it. Use that energy to improve other things in your life. There is always a way to improve. Find a path between things you can’t change and things you are too scared to change.