You are only ruined if you continue with your whining, negativity, narrow outlook and indecision.
Let’s get one thing over with – you say the professors “are not used to someone of my academic ability or ambitions” and then you admit that the science and math classes are so hard you can’t handle them, and you have so little ambition you aren’t willing to try so you bypassed your top three choices of majors. So don’t think too highly of yourself. You are not above the university you attend, or the professors who worked hard to get their jobs, in a time in which about 1 out every 200 PhD holders succeeds in becoming a professor. If you were truly of such superior ability and ambition, you wouldn’t let some weed-out classes weed you out, unless you discovered that your interests truly lie elsewhere.
You still haven’t figured out what you want to study. The topics of “economics, chemistry, biology, pre-med, pre-law or economic science” are all over the place. The types of internships and volunteer activities and research one pursues in college if they are set on medical school are vastly different than what is appropriate if someone has their sights on law school or an economics career or science PhD. You need to pick a direction and be focused to get the best results.
It doesn’t matter that you are stuck in corn and soybean country. You can complete a paid summer internship anywhere in the world, or even virtually. Savvy students apply to summer internships at cities around the USA and abroad. The internships are advertised starting early in the fall and continuing until early spring. They also seek out research opportunities on campus or in the community. And if their university doesn’t have a club they like, they start a new one and become the president of it, developing leadership skills. They also participate in competitions to try to win recognition for their abilities, and they often publish their work online, start businesses, blog about their interests and do all kinds of things.
I suggest that you take some career aptitude and interest tests online or at your career services office, to try to narrow down a suitable path and major. Then brainstorm over the possible things you could do to gain experience while you pursue your degree. Use your imagination. Ask your advisors, professors and others for suggestions. Read about top students at your university and what they have achieved. Look up student profiles on LinkedIn and elsewhere to get ideas. Once you have more focus on a specific path, it will be clearer to you how to proceed and find the best opportunities. You can always attend a more prestigious university for graduate school.
In the meantime, try to be more positive and optimistic. If you are down in general, it may be that you are depressed and it really has nothing to do with your university, in which case you should seek out counseling. Depression can blind people to what is great in their lives and to all the possibilities, and also lead to indecision. So be sure to address your emotions as you also figure out your path with academics, activities and career.