Hey Agent so sorry to hear you were unsuccessful; your story really struck a chord with me because I know exactly how it feels. Last year I was unsuccessful after interview (for history) and I was totally gutted. As much as I'd told myself to be prepared whatever the outcome, the reality is so different. It hurt so much, I was pretty devasted. I turn 25 next week so I too had that worry about age. I too was so angry at the recent graduates/undergrad students that got on....seemed like they just strolled in.
But I didnt give up, I reapplied again to the same provider this year. I wrote in my personal statement that I had been unsuccessful previously and that I was determined to get in at whatever cost. I had a second interview and guess what....I got in and was delighted!
I know it sucks SO BADLY now but I'm a believer in fate, things have a way of working out how they were supposed to. You already have such great grounding and experience, get their feedback and next year apply AT THE EARLIEST OPPORTUNITY and mention how you've taken their advice etc. Your determination and passion will surely shine through. Because of family commitments I too only had one place to apply.
So don't give up, lots of hugs!!