Admitting defeat is the wrong way to frame the situation. You have learned a lot and gained a lot of experience. There has never been a better time to market your skills, to companies all over the world, and see what is out there.

Your company compensates you for work that you've already done. You are not paid in advance. You owe them nothing. Be respectful, professional and polite... but, always do what you feel is the best thing for you.