PhD required to be a Psychologist or Clinical Psychologists. With only a master's degree, you might qualify as a counselor, e.g. Marriage & Family Counseling, etc, depending on which master's degree you earn.
Glutted market. Psychology is one of the most popular undergraduate fields, and practically everyone then needs to go on to grad school (assuming they qualify) to work in the field in some capacity. There are few full-time jobs, plenty of competition. Most cobble together two or more part-time jobs, or join a practice - and that means you are basically self-employed with no salary. Paid based on percentage of revenue from your own clients.
It is possible to earn a very good living if you are very good, build an excellent reputation over at least a decade or two, and build a solid, busy practice. Most consider themselves lucky to contribute with spouse to ordinary middle-class income.