I think it's very possible to be a professional cardplayer, though as you mentioned, emotional control is so key. I was semi-professional for a while, working 3 days a week and playing 7 days a week at the casino. At times I would listen to Eckhart Tolle's "Practicing the Power of Now" once a day to help me focus and learn to keep my cool.

It's a great game; I love NLHE most of all variations.

Thanks for sharing your story.