You will learn how to appreciate your breaks. To me, IB isn''t harder than what I was used to before but rather, it is just more intense in terms of workload (which I''ll assume that you''ve already heard from the IB''ers at your school). Your marks may flucuate at the beginning due to the heavier workload and higher expectations but they shouldn''t drastically change in the long run. Also, depending on your work ethic, the hours of sleep you get will be in decline the more you procrastinate.
I remember when I was in IB1 ... I could do most of my assignments the day before the deadline and still get an excellent mark but as the year went on, I found myself sleeping at 11:00 ... 11:30 ... 12:00 ... 1:00... 2:30am. Of course, I eventually learned that that was not working for me and I had to manage my time more wisely but even so, I still catch myself staying up pretty late - not only because of homework, but just because of habit.
During the summer between IB1 and IB2 (well, I''m not sure how that would work for the Nov. candidates), try to get ahead in your subjects - even if it is just a miniscule amount. If you are not busy during the summer, try to get some reading done for your Group 4 subject (History in your case) and your Extended essay. I only wish I had the time to get a head start on my EE during the summer because it is due in a month and homework has been piling up lately --> More stress, less sleep.
I haven''t got anything else to say right now. Use your time wisely and importantly, don''t let IB run most of your life. Of course you''re going to invest more time into schoolwork but remember, these are your last years of high school. If you spend most of your time just studying and doing homework, you''re obviously missing out on something. Yes, there''s university but there may be friends you''re going to miss ... family that you''re going to move away from.
So, manage your time wisely and you''ll be fine ... I suppose