Yes, karma definitely exists in reality. It means that what you have done and what happens to you all accumulates inside you. It continually exerts an influence on you and tries to control you – it appears through your actions even though you don't want it to. Karma is always trying to conquer the self. That's why in order to truly live your own life instead of following the orders of Karma you need awakening and determination.

Here's a particularly illuminating article on karma. I hope you decide to have a look and read with some interest: http://www.members.tripod.com/tathagata2000/enlightenment_wh...