For a number of advisors, even the mention of "therapy" or "therapeutic" evokes a negative reaction. This resistance is often due to concern that they might do or say something wrong to a client who is venting strong feelings.
Reflecting clients' thoughts and feelings back to them with empathy and compassion is good, deep listening, not therapy, and cannot harm them. If the intensity of feelings being directed at you ever makes you feel that you're in over your head, it's time to consider referring the client to a therapy professional.
Another sign of being outside your zone is obsessing about particular clients. Thinking about them on weekends, worrying about them, and feeling overly responsible for them are all signs that you need to consult a trained professional, either for supervision or an outright referral.
You should never feel you're all alone on your own. After all, you don't expect to have to do tax audits or draw up a QPRT for your clients. That's why you bring in experts.
If you don't already have a good relationship with a trained therapy professional whom you trust, it could be time to start looking for someone who is comfortable with financial matters. In fact, it's a good idea for all advisors to develop a list of therapists, counselors, coaches, substance abuse counselors, 12-step programs, and so on.