Please answer need serious advice..?

i had sex with a guy on the 31st may 2011 were the condom broke and he came inside me so exactly two hours after sex i got the morning after pill, and took it so i was well within the 72hrs anyway i dont know when my periods are regualr anymore as on the 3rd april 2011 i suffered a miscarriage and did have a short period from the 15-18 may but havent had one yet in june. now what is happening is that i have been having bleeding on and off for the past two days so i dont think its my actual period i have tested for preganancy and it was negative which was yesterday i have /a/lso done a std check from sexual health clinic a week after the sex happened which was7/6/11 i also told the lady what date etc and she said it was fine to test a week later as i was having symptoms of causing weeing all the time. since then i have my results and they both were negative for chalmydia and gonherrea she did swabs for those so its not that she also gave me medicine for bv which cured me and did stop the weeing symptom so why now am i bleeding the way i am. am i going to miss a period too