my last period was on july,15,2010, to july,21,2010. I had sex with my fiance july,24,2010. On the 25th l started to feel cramping until the 28th. Also iam farting, a having lil heart burn, my nose was twitching for two days. and my breast are a lil sore. The cramping goes off and on. I also have a 21 day cycle. So my period is two days late. I dont want to jump the gun to buy a preg test what should l do?