To be honest, with a UCAT score like that it's very unlikely you'd get into GEM this year. I would seriously recommend taking a year out and redoing the exam in the next cycle. The rest of your academic performance is great, exactly what they're looking for - maybe take the time out to get some good relevant experience and try and save some money. GEM isn't as expensive as a second undergrad but it isn't cheap, either. As long as you look at where you went wrong in the exam and focus on where to improve, as well as getting a good strategy for the minute long breaks to calm yourself down and stay in the zone, your academics show that you shouldn't have a problem if you resit the UCAT next cycle. It is pretty miserable to work for it and not reach that the year you want to, but if you want to do medicine I'm afraid there are no GEM unis, and probably quite few undergrad med unis, who would be likely to take that score. Good luck with everything!