I lived in London for five years and it was the most miserable five years of my life, rent was £1,000 a month for a shared house in Camden, and with bills on top the majority of my salary was eaten up by living. I moved from London to Liverpool, my salary actually increased, and my rent halved for my own apartment. Now I have savings, my office is walking distance (8 minutes, to be precise), and the city is friendlier, safer, and being smaller it is made much easier for seeing friends and getting out more.
What London doesn't want you to know is that there's a whole country outside of it, with much better living conditions.
If moving is not an option, you can look at reducing and removing your debt using a charity, they arrange monthly payments straight out of your salary so that you're not building arrears, Martin Lewis normally has good advice on this sort of stuff: http://www.moneysavingexpert.com/loans/debt-help-plan – the same website will also help you lower your outgoings.
Most importantly, $50k is not a lifetime of struggling, and you should look at getting a payment plan sorted before it becomes usurious. I've seen debt do horrible things to people and families, it's better to fix the roof whilst the sun is shining. Talk to someone.