I am trying to conceive. I was on the depo shot for one and a half years. My last shot expired about 9 months ago. I had a lot of spotting all the months after that. & I had my first real period starting on Jan 25th 2009. I'm pretty sure that I ovulated again the month after that (which would be this month) because I had the egg whitey kind of cervical mucous. So I had unprotected sex with my parter of two years then. Well, I've missed my period now. & I've taken two home pregnancy tests, both negative. It's been exactly 15 days since I had unprotected sex. I took the last test yesterday (-). I have had some pregnancy symptoms. First it started off with just sore breasts, then it went to my nipples being really sore,& I've been feeling nauseaous once in awhile. why are my tests coming back negative?