Sixth Form options

You don't need to have a clear idea of what you want to do yet, but you'll find that there is essay writing in most subjects except mathsy ones. I did psych and it was interesting but very exam focused (might have just been due to my college). Always keep in mind that if you ever realise you would like to do something more science related, often biology or one core science is needed. I found that when I was applying for uni a few courses I was vaguely interested in required biology. That being said it is not essential at all and psych itself is classed as a social science.
I would suggest just picking subjects you are interested in as you will excel at those more than the ones you aren't and come out with better grades. Maybe watch some youtube videos on what the subjects are like and you can get a clearer idea of things?