Witch as in Wiccan
No. In modern practice, Wicca is a very specific set of traditions that are part of the umbrella of Witchcraft, with well-defined beliefs and practices (such as believing in the Wiccan Rede and the Law of Threefold Return, using a common framework for ritual and myth, etc...).
That is not me. My practice is much more individually-oriented (old school Wiccans will tell you there is no such thing as a Solitary Wiccan), and not bound by Wicca's customs and ideas. I am closer to being a Shaman than a Wiccan, but I am not a Shaman either. I am simply a Witch. Or if you really want to be specific, a priestess of Hekate.
Is Karma religion?
It is an idea embraced by some religions and philosophies, to one extent or another. The basic idea being that what goes around comes around.