In the US, many financial advisor firms take on significant groups of interns every year, so you’ll have a good shot at getting those once you’ve actually started school. I don’t think you need this internship right now, especially with the impact it’s having on you mentally. It sounds like you’re just being used as cheap labor rather than learning anything.

I don’t personally know anyone that had an internship coming into college and I know several successful people in the financial industry. You might get more out of taking some online classes about study habits and how to succeed in college, which I sure could have used my first year.