Applying for joint Biology & Psychology / Biological sciences but a-level subjects?

Hello, I take Biology, Geography and History, and I got AAA at AS. I've just started to look into university courses now (I had no clue what I wanted to do really) and I really like the sound of joint Biology & Psychology, or biological sciences. However, I'm aware that biology is only 'sciency' subject i'm taking and i'm thinking that, although chemistry/maths isn't essential for the courses i've been looking at, they'll take into account that I'm doing 2 humanities rather than other sciences or maths. I really regret not taking maths/chemistry but at the time of choosing my A level options, I just went with what I enjoyed at GCSE, not thinking that choosing the right subjects was pretty crucial. I'm not really interested in doing geography/history at uni. Do you think it's worth picking up chemistry AS this year, or will it not really make a difference? I feel that I've completely lost my chances of getting into uni doing the course I am really interested because of my A level subject choices boooo