There are a few different angles from which to approach this. While I cannot give you an answer, these are some general things you can keep in mind and questions that might help you clarify things for youself.
Expectation
- Do you have a clear picture of what is expected of you?
- Do you get recognition when you exceed expectations?
- When failing to live up to expectations, do you get feedback,
coaching and help to improve yourself and avoid future failures?
Goals
- Can you picture where you want to be in 1, 3 and 5 years from now?
- Do you have any personal goals of what you want to achieve and where
you want your career to go?
- Is your current job advancing those goals?
Motivation
See Herzberg's two-factor theorm
- Are your basic rewards (e.g. salary) enough to make you not dissatisfied (hygiene factor)?
- What does the job offer to increase your satisfaction?
Security and worth
- Do you feel that you are valued as an employee?
- What loyalty do you feel towards your employer?
- Do you take pride in what you do and the company you work for?
- If things got tight, do you think the company would prefer to improve you or eliminate you?
Generally, my experience is that people who are satisfied and enjoy their work, who respect and take pride in themselves and the company they work for, they will also perform very well at their jobs.