I had IUD placed in March 2007 and removed towards the end of 2008....Now I think I might be pregnant. Am I going crazy???

I have 3 kids and I don't remember pre pregnacy but here goes. I had my last child in 2007 and had the Mirana insertd in March 2007. I didn't like it so I had it removed either Nov. or Dec. 2008. I have had several periods since then but March 27 and 28th. I had "pull out sex" a couple times. Now going off my previous periods since removing the Mirana. I was suppose to had come on last week...but my stomach has been cramping like crazy and no period. I am havingn white discharge though and I have taken a pregnancy test and it's negative. Is it possible I'm pregnant and the hormones hasn't showed up yet or am I tripping out?