My last period was July 14th - 17th. I had unprotected sex on the 23rd. I keep track of my period and fertility percentage on an app. it estimated that I ovulated on the 25th. my next period was estimated to start on August 8th, and it is now the 12th. I have had slight cramping, but not as strong as they usually are before my period starts. I have also had one major random headache a few mornings ago, along with very tender breasts every day since the 7th. One night I also noticed that the veins in my breasts were very large and more visible than usual. I took two tests the day of my missed period and it was negative. But last night I decided to test again due to the fact I haven't gotten my period yet, and still got two negatives. Im super confused. Is it a possibility that I am pregnant and its just too early to come up positive? Someone please ease my mind, I dont know what to think!!! 
