The terms therapist and counsellor are often used interchangeably. A therapist usually has a Master's or Doctoral degree in at least one of a confusing number of different disciplines: social work (MSW), couple and family therapy (MSc), general counselling (MA), psychology (MA or PhD), spiritual care (MDiv), or sometimes - but not usually - medicine (MD). Therapists tend to focus less on assigning labels to people and more on helping them to address the issues that prevent them from living life fully. The counselling services offered here at Transformation Counselling fall into this category.
A psychologist either has a Master's degree or a PhD in psychology. A psychologist could be a researcher who conducts studies, a clinician who administers psychological tests and makes diagnoses, a therapist who provides counselling, or a jack-of-all-trades who does some combination of all the above.
A psychiatrist is a medical doctor who specializes in diagnosing mental illness and prescribing medication. They don't typically provide counselling.