i went on vacation w/my BF in 2004. the day we were flying back i was supposed to get my period--only it didnt come. and it continued to not come for 3 weeks! i was so panicked and stressed and felt awful internally b/c i was so stressed. i think i even took 5 tests *gasp* im sure it wouldve come alot sooner had i stopped worrying and it turns out flying messes w/your whole system but nonetheless, i know exactly how you feel. *hug* hang in there~