Hi startingnew,
There are actually a few differences in these careers;
First, a psychologist. All psychologists working in Australia must be licensed. They have University accreditation with a Bachelor's degree covering study of the mind. Out of the three professions you've described, this is the most common one that people go to.
A clinical psychologist is a psychologist that has done additional training at University (a Masters degree) specialising in mental health; such as learning more about therapies or mental illness. As such they often cost more than a psychologist.
A psychotherapist unfortunately does not have to be licensed. They are pushing for it to be mandatory but it often means clients need to check that people have done some study. They may be Psychology graduates or only do a shorter University course.
Although all of these people can focus on different things happening in your life, a psychotherapist is more interested in the 'sense of self', and the things that shape us; like our childhood or any trauma. They are also more likely to have long-term clients.
