The only university that looks at UCAS points is Barts and that's just to decide who to interview.
UCAS Points do not matter. What matters is that you have at least AAA at A-Level.
Try to get work experience in a hospital or with a GP to help you to better understand the role of a doctor. Also, do voluntary work in a hospice/care home (i.e. in a 'caring' environment).
I'm guessing you're in Year 12?