If you have to then so be it, but I'd personally advise against Career Development Loans (before you know it, you'll be in debt up to your eyeballs ... and at some point in the future - when you'll probably need to be saving - this money will need paying back!).
If you can't secure funding, try to get a job that fits around your PhD (e.g. part-time lecturing if you can get it, or a job that requires no 'brain power' - i.e. stacking shelves/working in an office).