That's cool if you've found what you love. For me 15 years of just shooting this and that has really lost its appeal. I know because I don't sell or get my images published (I never tried to) Im considered an amateur but Im at the stage where I need more, regardless of making money or not from the work.
I know a professional is selling a product so it makes more sense to specialize and refine what it is your selling so the clients know what to expect. To me though I don't see why because I have the freedom to shoot anything that's what I should do. I hate the word amateur anyway because it implies you don't know what your doing lol and Ive seen many pros producing work that doesn't come close to so called amateurs.
Anyway Im going off track and thinking out loud (never a good thing). Mark was right on the money for me. I need to bring more creativity into my work instead of it being so random. I need to design and build my images from the floor up with my own vision.
"Amateur" and "Professional" are often thought to define the level of skills, like you said, 'amateur' implies you don't know what you are doing. But then how would you define "Semi-professional"? I don't view those as level of skills. They are supposed to define the status of pleasure or business. 'Amateur' means you do something for a hobby and don't want to be paid, don't forget that even someone who could be really so good at photography could still chose to take photos just for pleasure and not being paid. 'Professional' means you get paid for doing something. Just because you are an amateur, it do not mean to imply you are rubbish, believe in yourself. Beside, anyone can set up a business, get business cards printed, say "I charge £xx per-whatever" and yet do a sloppy work.
But being professional do not mean you are supposed to be specialist in one thing, being professional means you get paid. Of course, sometimes you would chose to specialist in one subject, becuase doing the same subject over and over again and again would mean you get more better at it. For example, if you do still-life, the first time you try it, you may take ages to set up the camera and lightning, you may also get the lightning wrong, but after a long time, you start to get used to it, you could set up the flashes blindfold, and you have learnt from your mistakes and improve your skills. But remember, being a specialist don't mean you are stuck with one subject and can't do another. Say for example, you may be still-life photographer, and on your way to work at the studio, you find an armed robbery at a bank ongoing, do you don't take photo on grounds of "Nah! Not my style." or "Nah! My camera is suited to life-stills." or anthing like that? So even if you chose to become a specialist in one subject, you can still do general subject.
Correct me if I am wrong, don't football players sometimes train as a goalkeeper because sometimes when the goalkeepers are injuried, one of the football players have to stand-in as a goalkeeper? Do he say "Nah! I'm central forwards! I can't be a goalkeeper!" What about a fighter pilot? I suppose if he's off-duty and is on a civilian 747, on holiday, and both 747 pilots dies, do you being the only passenger with flight experience, refuse to take over on grounds of "I'm a single engine fighter pilot, I don't know how to fly a four engine jumbo jet!"?
You can be specialist in one subject yet do general photos. You could specalist in one subject (say for example fashion or Formula One), doing the same subject over and over again and again, improving your skills, and sell your work to the related market (say
Woman's Weekly magazines or BBC Sports) yet when you're not working, you can still do general subjects, like landscape or whatever just to relax.
So far my shots have never really been pre-planned even when working on a theme. I shoot what I find that suits the concept Im aiming at and go from there. 
that said while I now pursue that genre professionally that will not stop me giving other aspects of photography a good go 
