@rjh - The first thing you need to know (if you don’t already) is that since digital photography has become so widespread, now basically everyone can be a photographer, so your competition is going to be fierce. I’m friends with a designer who told me that one thing he’s noticed over the years is that companies that used to employ professional photographers to shoot their brochures, portraits of staff members for annual reports or photos for their website now rely more on one of their staff members who just happens to have a digital camera and roughly know his way around Photoshop. It’s simply a cost-cutting measure.
As a professional photographer I can tell you that it’s a vastly different experience to being an amateur. The hours are long and the pay isn’t great and chances are you won’t have the opportunity to express much artistic license. In fact you’ll probably spend more time in front of a screen than actually taking photographs.
I don’t want to deter you entirely, though. It’s still a viable career option, but only if you do it for the love of the work. It’s certainly possible it might turn photography into a chore for you which would be unfortunate, but if you’re talented and you love what you do you’ll find a way to make it happen. It’s all about finding out which niche is right for you. Good luck!