They really are the hardest exams I think - too much crammed into two short years, so you never get time to really 'think' properly.
I did Psychology at Uni (10 years ago!). It's a brilliant subject - although not without its flaws of course.
If you get a course that teaches you how to research and gives you the tools to be able to evaluate and criticise the stuff you read - and think for yourself - it's the best subject ever, as it takes in pretty much everything including all the 'big' questions, including 'Is there actually any point to Psychology'!
Hated the statistics though - gaaah.
Was going to try and give you some helpful advice - but I also found it hard to motivate myself to be honest! Still do. Plus you've solo (and vodka) to distract you.
If it's any consolation, I did fairly crap in my 'A' levels due to extreme apathy, but still got into a good Uni on a 'easier' related subject, and took Psychology as a minor subject. Provided you did well enough in the 1st year exams, you could change it to your Major - so that's what I did. Voila!
Good luck