I don't know if you should change careers, of course; only God knows what is best for you in the future. Have you asked Him to guide you? I hope you won't lose sight of the fact that your job is a very important one. Yes, I know it can be discouraging to see people who never seem to learn from their bad decisions (pastors and other counselors face the same problem, incidentally). But not everyone is like this. Some people do learn—and every week you also help people who are the victims of accidents or illnesses they didn't cause. In other words, don't look only at the negative side of your job, but at the positive side, too.
Let me suggest you also examine your life, to see if you're letting your job burden you too much. Do you get enough exercise? Have you learned to relax and get away from your responsibilities? In the midst of almost overwhelming demands on His time, Jesus told His disciples, "Come with me by yourselves to a quiet place and get some rest" (Mark 6:31). We aren't machines; God knows that we need times of rest. In addition, see your job as a gift from God. Yes, it may change in time—but in the meantime, ask God to help you be faithful. The Bible says, "Whatever you do, work at it with all your heart, as working for the Lord" (Colossians 3:23).