I was supposed to have my period yesterday, August 17 and up to now, it still haven't arrived. I had protected sex with my boyfriend last July 27, 6 days after the last day of my period, according to my calendar, I'm supposed to ovulate from July 31-August 4. Up to now, I still don't feel any pms symptoms although last week I feel nauseated and bloated, and somehow sensitive to smell. But starting this week, I don't feel anything aside from my back pain and sharp pains below my tummy(uterus area) that goes away easily. I'm so paranoid and stressed. Can the sudden change of time of waking up affect my period, because I used to wake up around 11 or 12 noon during vacation but when school started last week, I started waking up at 5 or 6 am. This is already bothering and stressing me out for weeks now thay I'm not experiencing any of my usual pms symptoms. I also took a pregnancy test yesterday when I realized I missed my period, and it said negative. Is there any chance that it was wrong and that I am pregnant?? I've been reading posts on google that missing pms symptoms can also mean pregnancy. Please help me.