Normal signs of period, but period is not here yet. Should I worry?

I am in college, and I am very sports active. My boyfriend and I have sex, but I am on birth control. I chart my period...and it usually is here every 26-28 days, but today, is the 32nd day and my cycle has not came yet. I was recently sick with food poisoning about two weeks ago, and I have been stressed. I am bloated and everything just like I always am before my period, it's just not starting, and it's freaking me out. I am very emotional, and am having all the symptoms I normally do before my period. I have also had a lot of diarrhea lately. Am I just being paranoid? Or is there any chance I could be pregnant? Everyone is telling me as long as it comes by the 34th or 35th day it's fine...but what if it doesn't? I am just very paranoid and would really like advice from someone who knows all about periods and pregnancy.

Thanks so much...

I hope someone gets back to me