I had unprotected sex April 6th and 9th and I got my period on the 10th like usual. My period is normal 7 days long and light but this time is was 5 days long and heavy. It's now May 19th and I am 9 days late which hasn't happened since my last child. I have been really nauseous, bloated, constipated, gasy, tired (I could sleep all day), and my lower back is killing me. I have taken a pregnancy test but it came back neg, as did the one for my first child. I am really confused, please help.