Don't kill your body just to get through some exams... Most people fail at least one subject through their college studies, according to my head of department.
I noticed that my grades were sliding from quite good to just borderline when I got to the 2/3s point of my degree. For one of my end of semester papers I put in so little effort and churned such an utter load of crap that I only passed by a few marks. My teacher was quite friendly too and I was the only guy in a class full of f- king bra-burner militant lesbians that actually offered something in the classes, so I believe he let me pass based solely on his discretion. It was then that I decided that I needed to take a break from study and come back after a year with a fresh mind and a slightly more padded wallet, so I took intermission and worked for a year.
Studying full time and working a couple of shifts a week just to pay for the bare essentials like food and petrol just to get to uni really sucks a lot of balls, so I decided to get away from that and start making some money so I could waste it on my car, a gaming PC, a massive TV and PS3, lots of expensive beer and whatever else I wanted.
It was the best thing I could have done, I'll be going back to uni next year with a fresh mind after what ended up being an 18 month intermission. I've had time to work full-time at a job that will be perfect when I go back to uni and generally turn my brain off and relax.
I have also decided that one must treat uni (or college for you yanks) like a 9-5 job. Even if you have one lecture and a class and are only needed on campus for 2 or 3 hours, stay there after and study. Do the homework that day, do the required reading and start borrowing some books from the library. It's all too easy to fall into the "sweet, I've only got a half day, I can do such and such for the rest of the day" attitude. Whatever you do.... don't go to the bar before lectures. Nothing makes it harder to get through a lecture and get anything out of it than the 'beer tireds'.
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Even if you tank your exams and fail everything, you'll only have set yourself back six months.... in the grand scheme of things, that's pretty minimal damage.
Just take this position that you're in as a valuable lesson that sacrificing an hour a day during the semester will save you stressing out and pulling all-nighters just to get the grades you want. Come back next semester fresh and calm and just do the leg-work when you should. I'm sure that you've got something of a brain between your ears, so it's not like you'll have to bust your knackers every night doing course work just to get through it.
Hopefully, I can take my own advice in my final year and get the work done.
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Good luck, mate.