When you say "last pill of the month," do you mean placebo pills or pills right before your pill-free or placebo week?

i meant pills right before my placebo ones. sorry if that wasn't clear.

It is probably unknown whether your pill got absorbed or not. Either way, though, it just means your pill-free week got extended to 8 days instead of 7 (to the best of my understanding).

http://www.ncbi.nlm.nih.gov/pubmed/9704763 ?dopt=Abstract

This link is a study that proved that women whose pill free week was extended to 10 days still did not experience ovulation in those days. So, based on this study, an 8 day break instead of a 7 day break probably would not result in ovulation. And, since your pill could well have been absorbed, you may not have anything to worry about.

Use back-up for 7 days into your new pack, just in case, and then your protection will for sure be back to normal.
Although I doubt you have anything to worry about as far as pregnancy goes, taking a test could give you reassurance.
Good luck!