I dunno, I wouldn't worry about the deadlines. Professors almost always would rather read a late but interesting essay than an on-time, boring essay. And 18-25 is a hard and shitty time for many, many people.
It's nice to have someone who is interested enough in the subject to take the time to write a good paper other than just turn in a shitty c-grade paper on time, which is what a lot of people do. People who don't meet deadlines are often perfectionists.
All of my work was late, last semester. Two of my professors were late in returning their grades. It's just life.
Don't worry too much about the reading either, and about the grass being greener in other disciplines. These days, you can change direction in a masters course later on.
I'm sorry if this sounds dismissive...I feel for you. And I said many similar things at your age - about not deserving the grades, etc. I just also have a headache right now.