Ok. I am 18 years old and me and my boyfriend had sex 38 days ago which was February 14th. My last period was in January. Since we had sex I have been nauseas but I haven't thrown up, I have been tired, urinating more, and just very little pain in my breast , my stomach feels very bloated, and I have had cramping. I have had many pregnancy tests but they have all been negative could I still be pregnant??