Pharmacy Vs. Medicine

I have no idea which one is right for me, I wanted to do pharmacy for ages and am doing my A-levels now, ones I picked with pharmacy in mind. But I was not sure if it was me or my mum who decided that for me and I started looking into medicine and decided I really want to do that.
Now I am a bit daunted since I feel like if you want to do medicine you don't just decide one day, but it is your life's passion. I still do not know which pathway is better suited to me or which one will bring me more satisfaction, or if I am even good enough for either.
How am I supposed to know if I am good enough or which one I am better suited to/is right for me?

Everything is decided "one day"...people aren't preprogrammed into wanting to do X profession from the day they are born. The ones who have a strong commitment to medicine from an early age I strongly suspect tend to be those whose parents or other close family members are doctors so they have more awareness of and exposure to it. That doesn't mean those without that early exposure to the profession can't become a doctors...

You certainly can go into medicine even if you've just now considered it, although as above you will need to do the requisite work experience (which will also help you gauge if medicine is for you) so look at sorting that out. You can then sort out the UCAT stuff and aim to apply next year before the medicine deadline of 15th October