What to do after screwing up at a job interview?

You probably should have stuck with location as the reason for leaving. There really was no reason to bad mouth your current employer to your potential new employer. If you still get the telephone interview I would stress the postitives of your current job and try to emphasize the fact that you live much closer to the employment location you hope to get. But honestly, it sounds like you blew this one. Just try to be more prepared and more relaxed in the future. Don't knock your employer. The potential new employer never wants to hear how bad you think your employer is. Stating that you are seeking new challenges and hope to expand your knowledge and experience is a much better idea.