I took my last bcp on july 20, 2013 had cycle on july 24 and on august 21 the usual 28 day cycle. i am now on day 34 could i have post pill amenorrhea?

Unlikely: Birth control pills, unlike the depot Provera (medroxyprogesterone) shot, don't stay in your system for very long after you start taking them, and definitely wouldn't affect a cycle this far out. If you're sexually active, consider a pregnancy test. Otherwise, delay could be due to swings/changes in hormones. Also consider thyroid, pituitary or extremes of weight (thin/heavy). Good luck!