Hiya, I’m a second year psychology student. The first book I’d really recommend is Psychopathology (2nd ed) by Davey. We use it in our clinical lectures and it covers a lot of core material.
I’d also recommend a book on Social Psychology, either by Hogg & Vaughn or Sutton & Douglas. These are core to Social Psychology, and something you will definitely study.
Possibly think about a biological psychology book, for example An Introduction to Brain and Behaviour by Kolb & Whishaw and Cognitive Psychology by Eysenck.
It’s fantastic that you’re doing some background reading! Just be aware that university core texts are usually very expensive. If you can get them from a library that would be ideal, especially as these books might not be on your university core reading list. If not, try getting them second hand from eBay or Amazon.
I hope this helps!😊