Hello im just wondering if anyone can give me some insight on this issue

Now back in august i was supposed to have a period at the beginning of that month 8-3-2008 or somewhere close to that. i didnt get one at all which has never happenend to me before but the thing is that i took 2 sets of Plan B almost back to back a couple of weeks before this and so i thought that maybe it was this and it would come later but it never came so im thinking i have skipped or missed that period.i also took mutiple pregnancy test and blood test they were all negative so at this point i knew i was not pregnant. Now here is september and now starting on the 17th of this month i got back on birth control pills and i had intercourse ( stupid i know) during the first week of pills but since i didnt haver a period i dont really know if at that time i was ovulating or not so im confused as to if the pills is going to put my hormones back on track and start my periods again or snice i had sex that week will again throw me off and then go down the path of taking pregnancy tests and things like that so im scared and dont know what to do at this point. Im on my last week of pills so this upcoming sunday will be the placebo week and i hoping that my period will come what do you think?