There are indeed professional gamblers out there, but it takes lots of practice and learning, and it's definitely not something for everyone. You've got to have lots of discipline to make money from gambling, and an ability to adapt to change- this Reddit thread features a person that is supposedly a professional gambler answering questions about his occupation and other things, and I think this is a relatively interesting read, but it's going to take lots of time to gain the skills to make money from gambling; again, people put thousands of hours into this, and it's definitely not for everyone.