To dream or not to dream? That is THE question

So after 4 med school rejections I have decided to take a gap year and reapply next year, but I just can't get something out of my mind. Drama School.  I have loved acting ever since my teacher introduced and instilled in me a love for something that I never knew I could do and now as I approach the final few months of my school career and consider what my next step is in regards to my future, I can't help thinking that I should be acting. But I just can't shake medicine out of my head. I guess that I am scared of following my dream and then it not working out and having nothing to fall back on. And then I also wonder, do you really need to go to drama school to be an actor? I mean you can either act or you can't right? And what can paying £9000 a year really get you in terms of being able to act if you already can? But then I see all these actors who I love and how they attended drama school in some form I wonder if I would ever be able to make it without attending? Would it be good enough to just attend summer courses and the like at various acting schools rather getting in lots of debt completing an acting degree? 

Anyway, if anyone has any advice I would really appreciate it. Thanks! 

Megan