You can be whatever you want to be, just because you choose certain subjects doesn’t mean you are stuck on a path for the rest of your life!
If you wanted to do those subjects, then I think that you could be really successful in business, maybe start up your own global business in anything you could think of! Within law, there are so many different types of laws, you could specialise in almost anything! As a psychologist, you could combine it with business and be a business psychologist, training people in business, you could combine it with law and be a criminal psychologist, or you could stay in medicine and help people that way.
Hopefully anything! I think we get very concerned about what we can do with specific subjects, but with a good education and interest in most subjects, you can apply what you know to a lot of careers. Now obviously if you want to become a scientist or an engineer, it makes sense to study relevant subjects such as physics, mathematics, etc, (like wise for professions careers such as medicine), but please try and pick subjects you enjoy doing and have a passion for!
It is important to have an idea of what career you would like to do, but this shouldn’t completely dominate your education.