tl;dr: I would bet your MCAT is fine, I think the class is full regardless of what the facebook group says, go get in someone's face and yell at them why you want to be a doc, this process has been the absolute worst but I think we are better for it
It depends on how low your C&P section actually is. A 509 will certainly get the bills paid. I know someone with a 500 that's matriculating to a great medical school. Given that you interviewed at CU and received HPWL I would guess that they were able to look past your C&P score.
I think the chances that those 48 people don't have facebook or haven't joined the group are very high. I am almost certain (watch me eat my own words after posting this) that the class is full and that the only thing that will free it up is waitlist movement at other schools. That said there could have been waitlist movement at other schools in the past week that they have not processed yet.
I am rewriting my personal statement as we speak and have found the exact same thing to be true. Thinking for the last year about how dedicated I am to this career path and why has been profoundly affecting. For me, it's easy to know that I want something but difficult for me to really understand "why" until I encounter strong resistance. I met with my mentor at Anschutz yesterday and we decided that this probably wouldn't be my year despite HPWL. After that, they grilled me on my old personal statement and what I was trying to say. I was angry, frustrated, sad and snapped. I started yelling at them why I wanted to be physician and why I wouldn't settle for anything else. It was incredibly therapeutic. Not just talking or writing about why I wanted to be a physician, but yelling it in a short burst of anger.
The most frustrating thing about this career path, at least so far, is that it is slow. Becoming a physician is a slow, painful, and dehumanizing process. We already knew that though. I think that may be one of the only benefits of not getting an acceptance right away or even this cycle. Forcing yourself to think about how bad you want it in the most tangible way possible is terrifying but also crystallizing. Now I know how dedicated I actually am: even more dedicated than I was a year ago. I have a feeling that most of your answers are the same. I've learned to define myself by who I've become in my pursuit of medicine and not by my pursuit of medicine.