I agree with Reesha - go with how you FEEL in your clothing.
I'm only 4 pounds lighter now than I was 6 weeks ago. BUT, I've lost an inch off my hips, 1/2 inch off my waist and 1/2 inch off my bust in those 6 weeks. All that exercising YOU'RE doing is making you fitter and stronger too, and building more muscle. If the scale never budges, but your body changes shape as a result of all that fitness, you should celebrate it! So yes, using the "zipper method" of determining progress towards a goal is just as valid (perhaps more so!) than using a number goal.
Keep your chin up. You're a mileage rock star!
Susan