My last period was on feb. 28 2012 i had brieff spotting the following month around the time of my period but it went away quickly.I v taken a few pregnancy test at home and the doctors and all came out negative. I have had headaches, lower backaches , frequent urination , bloating for no reason, constipation, and i dont have an apitite very much anymore. Should i take a bood test to see if I could still be pregnant?