Swapping uni courses

I am currently over half way in my first year of an undergraduate degree in Sociology and American Studies. I don't like it though and have decided that I want to do nursing and then go on to do midwifery which is something ive been contemplating for a while but in a moment of panic applied for this course as I liked studying sociology at A Level and thought it was something that I would want o pursue further. I don't have an A Level in any sciences as I originally started a Btec in Health and Social Care to do nursing then dropped out to do A Levels. If I finished my first year at uni would I then be able to leave university to do an access course (a health one) and then go on to do nursing, or would they not allow me to do an access course as I have already gotten accepted into a university. The only issue here is I said, I don't have any science based A Levels which from what I've researched is usually the requirement for studying nursing. Thanks for any help/advice (and sorry for it being so long!)