Okay..so im really confused I think I could "possibly" be pregnant , but I took a test and it was negative... so I was supposed to get my period on Wednesday the 16th but I didn't and a few days later , I had sex on the 19th without protection ..then a couple days later on the 21st I had gotten my period but only had it for 3 days.. so im really confused then 13 days later I took a pregnancy test & its negative... so am I really not pregnant? Or was it too early for a test..