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I had s_x on the 17th & 20th of this month (march 2012) without using a condom, he just pulled out..my fertile days was from march 17th until the 21st..my period is due on April 1st or 2nd ..on march 27th i started experiencing cramps like i wast about to start my period (which usually doesn't happen until a day or 2 before my period) as well as nipple soreness (which again doesn't happen until 1 or 2 days before my period & only happened a couple times & doesn't last longer then a day) i took a 1st response pregnancy test in the morning on the 29th it came out negative..its now the 31st & its been 4 days since the cramps & nipple soreness started & i am still experiencing them, but now I am having pain in my lower belly like under my belly b___ton (it feels like a shooting sharp pain or like i pulled a muscle but it doesn't last long) my cramps is getting a little stronger & my nipple soreness is easing up a tad bit but still sore, i also took the same brand pregnancy test today (the 31st) & it was negative again but later on in the day i notice a little light pink blood (which i never experience before) So is this implantation bleeding? or its just my period about to start up? did i test too early since they say the hcg hormone doesn't show up until after implantation?...PLEASE ANSWER ASAP cuz i am so confused & worried i do have a doctors appointment on the 4th (in four days) but i just want to know if others experience this & for someone to answer my questions before i go to the doctors....thanks so much in advance