Is it really worth doing an MBA ?

That depends on a lot of things. Do you enjoy your "good job"? Is it a job that you would want to stay at for the long term? Are there any opportunities for advancement in your present job? If you have goals and want to advance in your career, you will probably need to continue your education. As far as the financial advantages, I cannot say for sure, but I would imagine that higher education would equate with higher pay, as it does in most fields. I would think that it might be worth it to tough out the next few years and finish your education. Remember, you will spend many, many years working, so it's important to be doing what you really want to do and not settling for "just a job".