When I was younger, I wanted to be a teacher when I grew up. Partly this was due to the fact that I wasn't aware of that many careers and partly because I loved being at school! What did I love about being in school exactly? I loved learning; I loved the structured environment; I loved the positive affirmation I received from teachers; I loved the rhythm of the academic year. Although I wanted to pursue a teaching degree, many people dissuaded me from doing that because, at the time, the demand for teachers was low.
Think about what you wanted to be when you grew up. Was it to be a rock star? A firefighter? A professional sports figure? A nurse? Maybe you are still pursuing that dream, or maybe you're not. If not, think about why you wanted to pursue your dream career. What was it about the career that excited you? Once you have identified what factors intrigued you about this career, think about how you can find those factors in other jobs. For example, if you wanted to be a rock star, perhaps you were dreaming of being famous. Well maybe you can be famous in your own circles. Perhaps you can become an expert in your given field and gain notoriety with that.
If you wanted to be a nurse but later realized that you get queasy at the sight of blood, think about what attracted you to the nursing profession. Do you like being in medical environments? If so, perhaps you can pursue another career in a medical environment. Do you like the aspect of helping people? If so, you can search for other kinds of "helping professions" that don't require drawing blood on a daily basis.
It turns out that I ended up becoming a teacher after a very circuitous career path. I love being in the academic environment comprised of students, classrooms, libraries and learning! So, don't abandon you dream career just yet. Either go for it or find an alternate dream career where you can do the things you love to do and still pursue your passion.