I'm am 21 years old I have a 1 year old daughter. I had my period July 16, 2013. It lasted 4 days and it wasn't a heavy flow it was a medium flow. me and my bf had sex july 23 with no protection and he came in me a little bit. I've been having headaches everyday now, constipated, mood swings, lower stomach pains, bloated, using the bathroom alot, and feeling nauseous. I took a pregnancy test in it came out negative. Does it mean I'm testing to early? I'm due for my period on augst 13 Should I wait then to take a pregnancy test?