As Kim answered, Aviation and Doctor are both huge fields with many diverse options. Airports and hospitals have very many positions with different requirements that serve different purposes. A doctor will require a lot more schooling.
I work in aircraft maintenance, and I love my job. Sometimes I think of myself as an airplane doctor. If I make a mistake, just like a Doctor, I can severely affect someone's life. You can get your Federal Aircraft Maintenance Technician license with 30 months of training, but the learning never stops. As technology advances, we have to keep up. Everyone I work with loves aircraft and all things mechanical. You have to be very detail oriented, and there is a lot of pressure to get things done, but you always have to focus on quality and safety. Most of the time, its a thankless job, if you do your job right, no one will even know you were there. Many times when the plane lands, people clap for the pilot, you never see the technician that spent all night to make sure that when you push a button, the engines start and everything happens as it should. But, there is something infinitely rewarding about watching your airplane taking off and completing its mission. My pilot friends love their jobs as well, and there is nothing else we would rather do for a living. Pilots deal with a lot of stress as well, after all you can't just pull off on the next cloud when something goes wrong.
My parents wanted me to be a Doctor, but I hate hospitals and can't stand the sight of blood and injuries or suffering people. But every Doctor I have ever met, loves their job. My nephew always wanted to be in the military, but due to his asthma, the military did not want him. Quiet by accident he stumbled into an internship in a hospital, next thing I knew he enrolled into a school and is now a nurse and loving every minute of it.
You have to find something that fits you. Ask yourself "what do you like to do?" "What are your interests?" "What are you good at?". Hopefully the answers will point you in the right direction. Remember not to judge yourself by the success of others, just because something worked for them, does not mean that it will work for you. Do some research and don't be afraid to try different things. Keep in mind that "Sometimes you choose a career, and sometimes the career chooses you". You have a lot of choices, but only you will know what is going to make you happy.