It's completely okay to not know what you want to do for the next thirty to forty years of your life, when you are only in high school or a freshman in college. This is a big decision, so just breathe. You're probably stressed because all of your friends know exactly what they want to do with their lives, but committing to one thing is hard!
Honestly, it is better to go into college undecided than to change your major after a year or two.
Explore your options! Go to a job fair! Most importantly, find something you're passionate about. Finding something that you are passionate about may take time, or you may already know. I have a heart for rescuing marine life, so I am majoring in Marine Biology. To be real honest with you, someone with a degree in something else could do the same thing I want to do. If you are passionate about something, you'll end up truly enjoying your job. However, if you're not, you might end up not liking your job at all. If you love kids, you could find your place in teaching. If you enjoy helping others, you could look into nursing or social work. You could also minor in something else, or double major, so you can do more without throwing your major out the window. There are so many different paths you can take, with the same degree.
Take some time to find yourself, and then start looking.
More than likely, you will find a degree that you find interesting and would like to pursue. My advice would be to apply for as many colleges and scholarships that you can senior year of high school. Then, pick the school who offers you the closest to their full tuition. This way you don't have to take out as many loans. If you have multiple options, go on a tour and see if one school feels more like home than another. Then, find a major that you think would suit you. Finally, just stay focused on your classes and enjoy your college experience.
Psalms 46:5 says,"God is within her, she will not fall; God will help her at break of day."
Basically, this verse is telling you that no matter what happens, God will be there to catch you. If you rely on God, you will be successful. I'm not saying don't study for your test, because you should and need to for you to be able to pass. You have to meet God halfway. God will never leave nor forsake you, so just trust in him and you will come out of this stronger than before.