There are so many occupations in this world. You should use your maturity to choose the right school. When you go back to school, you will see how fun it can be. You'll strive to get a good grade and it's like a nice intellectual game rather than torture. Don't be so afraid to go back to school!
Regarding the choice of occupation, set your goals in different terms.
Talents
Don't just think which job you would like to do, but also think which job would like YOU. Maybe you want to be a biologist traveling around the world and be recorded by Travel channel, but not everyone can do that. There are very few people that were chosen to do it.
You need to be brilliant at what you do regardless of whether it's cooking or nuclear physics, teaching or engineering. Only then you can enjoy your job and progress as well as make good money.
Maybe you have precise hands, maybe you are good at figures, maybe you are a good orator... There are so many character traits in everyone of us, you should thoroughly examine all of them. Your friends and family might be more objective than you. But don't let them mislead you!
Money
Some jobs are just more profitable than others. There are many lists that show which jobs pay what. You cannot be a pilot instructor and live in a fancy villa. Don't study computer science because Bill Gates made it or political science because politicians are successful. Find a compromise between your financial needs and preferred jobs.
Desires
I believe that the most important thing about jobs is how much you make, but the second most important thing is to enjoy your work. If you're an artistic, introvert person that loves being alone, you will find it hard to work with lots of moody people or children; you will need peace. If you like to help people, consider that when choosing your future occupation. You like animals, but would you be a veterinarian?
Working habits
If you're not very enthusiastic and motivated, if you lose your inspiration easily then don't choose hard schools like medicine, engineering or science. You might never graduate. They require a lot of hard work, sacrifice, sleepless nights, and concentration of your mind. If you're rather artistic and don't like figures, don't choose finance. Take into account that if you don't like the school, you probably won't like the scope of jobs offered within that particual degree.
Let us know what you have decided please!