It is unethical for a psychologist to leave themselves in a vulnerable position when trying to assess a client. We may be affected, but as far as I know you're not supposed to show it affects you because you are trying to make the other person feel better and there is a chance that they might think they're hurting you by talking about their problems if they see you crying.
This professional recommends the following next steps:
- If you can and have someone near you that is, ask a licensed psychologist how they deal with the emotions that may surface when treating a client. I know a few and they all handle it differently, so someone that you know could potentially have a detailed answer to give you an idea of what they're everyday life is like.