Vocation is a set of skills that you bring from when you were born. Skills is when you are born with the ease of doing something, but you did not know already born, you are born with a tendency to have the skills, it is necessary to be exposed to the subject so you know if you have skills or not.
Although many people choose their profession for the wrong interests, a career is a search increase in their profession, something you want to do a lifetime and it all depends on your interest in the profession. That is, a career is a path you want to follow to achieve your career goal.
A profession is the act of professing to exercise the office of something. Most professional choices are for 'wrong' interests and end up bringing the dissatisfaction of those who exercise it. The professional choice should be the composite of their skills and tastes, thus leading to descorberta of his vocation. However it is very common for people to choose the profession by economic interest or status. My professional choice, I've had decided, but now I'm suffer doubts because I sow that have somethings I would like too and I can see me working in it. But my main choice is civil engineer because I like math and projects of house too. So I think I would like to work in it.
Job market is a large and demanding number of offers and requests for work. For example, the medical field today is a technically great field, but also very demanding. And as an engineer professions is more difficult for an engineer to be necessary only one in companies. The labor market has changed a lot over the decades. Today they require experience, but prefer new people to work, require use of technology and the person understand the technology and depending on the area they seek even more.