Late period, excessive stress. Pregnant?

i'm stressing out over this, so i'd like some other opinions on it, maybe to settle my mind once and for all. my boyfriend and i usually use condoms, but sometimes we use the pull out method. terrible, i know, and after this i'm going to start birth control as well so there will be no more future scares. i don't remember the exact dates we had sex, but my last period was february 4th. my cycle for the last three months has been every 31-33 days, so i was due around the days of march 7th-9th. today, it's march 16, and still no period. i went to the gyno on march 11th, and she told me they did a pregnancy test and that it came out negative, so that put my mind at ease a little bit, but now i'm stressing out all over again because it's still not here. lately, i've had a lot to deal with (ie: fighting with my boyfriend, planning a surprise party, and i have surgery tomorrow), so i've been thinking maybe it's stress that's causing it to be this late? but i've also read stress can only delay ovulation, and i don't remember exactly when the stress started, and if it was around the time i was due to ovulate. i've had a pregnancy scare once before last year back in august, where my period was 40 days late or so, but i think that was because i was stressing out over being pregnant. i'm young, and i can't afford to have a baby right now. should i take another test? right now i'm feeling a bit bloated in my lower abdomen, and i've been having frequent discharge all day. a couple of days ago i would get really dizzy while standing up, but it's stopped now. no lower back pain (that i don't have already, i go to the chiropractor frequently), no headaches, and my breasts aren't really sore or anything. maybe my period's on its way? i'm so confused.