It sounds like you are doubting different aspects of your life - career, education, children - so it's not just one thing that you aren't sure you can do, it's feeling unsure of yourself. I think the question is not whether you are capable of doing these things, but do you want to do them? Are they things that you want in your life? Because if they are truly things you desire then you should pursue them because they will make you happy. Then you just have to trust yourself. I mean, if it's a logical thing like will I have the time to manage three foster children and the career I want and the schooling I want, then that is just a logical time constraint. You have to be able to manage the time in your day. But it sounds like all that is holding you back is the fear. So ask yourself, are there reasons you are apprehensive - not enough time, or money for school, or for another foster child, etc.? If there are concrete reasons think them over. If you are simply doubting yourself, that's another story.