Oh man, I feel that. Next time, I'd just tape the new cable to the old one and pull it through (if the old one isn't stapled down, that is). Saved me a ton of hassle once.
Ugh, that sounds like the worst. Been there with the cobwebs and the mystery pipes and that one spot where you just can't turn your head. You finally get it fished through and then realize you're on the wrong side of a floor joist. Absolute nightmare fuel.