Just thought I'd say hi - saw someone last year do this when I was in your position and I found it helped. So yeah, this is what you're reapplying for (re - picture below)!!! don't give up hope! I had four rejections last year but didn't give up, I reapplied this year and guess what... I have offers now!
Don't stress about getting jobs as HCA or whatever, I didn't (did try though) it's not essential but hey, if you can then go for it, you'll probably get some useful experience from it. Try getting as much out of the gap year as you can, travel, work to save money, get more medical work experience, tutor to keep your knowledge up, do whatever, just don't sit around doing nothing!! Medicine is so competitive that sometimes I honestly do think it comes down to luck, however you can maximise that luck. Research admissions processes and apply to those where you have the greatest chance: this is helpful
http://www.thestudentroom.co.uk/wiki/applying_to_medical_school_using_your_strengths and for those resitting, that's fine but check out this first:
http://www.thestudentroom.co.uk/wiki/medical_school_resit_policies a quick note for interviews, get an overview of what to expect using this
http://www.thestudentroom.co.uk/wiki/what_you_should_expect_at_a_medical_school_interview and then arrange as many mock interviews as you can. Confidence is key and confidence comes with practise, same with any other exam, which is essentially what an interview is, a verbal exam. About being too rehearsed - if you're confident enough you wont sound it, however I don't really think they care too much about it anyway, I think they'd care more if you weren't rehearsed at all as it could convey a negative attitude with regards not caring or poor management in providing time to prepare, who knows. Anyway, GOOD LUCK and ENJOY IT - I know I have and will continue to till med school starts in September!!!!