Hi I am a Clinical Psychologist with a private practice in San Francisco downtown. I work with school-aged children, adolescents, and adults.
Your anxiety sounds like normal to many people of your age (19). It's difficult to decide and focus what to do next unless you got some guidance about work while you were in high school. Are you worried a lot now? That's why you started thinking of counseling?
I think your problems - difficulty focusing and staying on a job - are typical of people of your age. It can be difficult to decide what to do next after finishing a high school. You need to set a goal for the future and plan from the goal. If you do not know what to do next, there are things you can try - read books on career choice, sees a career counselor, talk to adults who have the job that interests you.
If you worry and are anxious a lot, you will benefit from seeing a psychotherapist for not only that you can manage your overwhelming feelings but also that you may figure out what you really want to do now and later.
you can email me if you have more questions. Good luck!