i missed my period,,my last period was in last month decmber...nd i had sex in dhis month january.....i had lots of pains,headach,brestpaing.sholderpain.lazzy...i'm always hungry....i test a hcg pregnancy test to day(january 25 2011) in the morning..and it shows negative,,,am i pregnant nd what shell i do to know i'm pregnant or not..plxx help me