What Causes Delayed Periods With Sickness And Headaches?

Me and my boyfriend had unprotected sex2.26.11 to 3.17.11. He ejaculated everytime. I dont know when I ovulate because im irregular. I had a temp of 99.98 on wed 3.16.11 and a fever friday 3.18.11 temp was 102.8. No period yet .why am I sick and I have stuffy running nose feel wetness and a major headache land want pasta and shrimp. Been pregnant before