Walking away doesn’t necessarily mean you are quitting.  Sometimes it just means that you are done.  It may be a sign that it is time to leave if you are no longer learning anything from the situation, or if you no longer like the person you are when you are in that situation.  It doesn’t mean that you are bad, or that other people involved are bad.  It may mean that you have gotten what you need from the situation, and it is time to move on.  Change is hard; you may have to overcome fear of the unknown.  And if you want to continue to grow, you need to know when it is time to leave.