I think that often we tie as many labels to spirituality as we do to sexual orientation and gender and so many other things. This shouldn't be necessary. Your spirituality, your belief, does not have to or need to follow anyone elses. Even within more organized religions you will find a variety of individual thoughts and beliefs.
I would not call myself Pagan, or Wiccan, or even Druid (though this is strongly tied into it). My beliefs have been gleaned from all of these, as well as Native American, Buddhist, and so many others. I am spiritual, committed, and I believe very strongly, but my belief is my own.
As far as karma is concerned. It is often easier to see the negative responses to our actions then the positive. It is so easy to take the good things for granted. A thank you, a smile, or simply a day where nothing goes wrong can be that karmic return. Never the less, it is always good to keep karma in mind. I have seen the results of such things in my own life. Karma has always made its presence very known to me, it reminds me often to keep on track and do what I know is right.