I'm worried I might be pregnant. Me and my partner have had sex more than once during the time I was ovulating. My period came four days early and was slightly lighter than usual. It lasted less than forty eight hours and prior to that I had been experiencing some symptoms. My breasts have almost doubled in size, my nipples have become a lot darker and larger. They are very senisitve also. My lower back has been hurting as has my shoulders and neck. I have been sick once but that was on the first day of bleeding. There have been cramping also. Could this be pregnancy or am I worrying for nothing?