Many, many people get rejected from Medicine at first attempt. Its competitive and a tough process to attempt at the same time as A levels or another degree. Take a year out, get as much 'people' experience as you can over the summer (work in an aged care home, work as a HCA, volunteer at a homeless shelter etc etc) and reapply in the autumn. Totally rewrite your PS. Play down all references to school or Uni and use examples from your w/exp etc that show you are mature. reflective, patient, compassionate, a good communicator etc.
Prague or any other overseas Uni may feel like a quick-fix answer, but it isnt. Be very aware that if you start an overseas course and drop out, most UK Unis will not be interested in you as they have a blanket policy of not taking people with half-completed degrees/transfers. The drop out rate from Prague is high - the reality of living in Prague isnt much fun if you don't speak the language, homesickness is common, and you will miss your family and friends more than you expect.