Had unprotected sex a week ago, ejcaulated inside of me. i already feel implantation cramps & i only spotted once. i know that i'm going to miss my period, because i didn't take ec. please help me?

Assuming you conceived a week ago and you do not want to get pregnant, you should wait for another week or 10 days then if you truly miss your period then you can do a urine pregnancy test. If pregnancy is confirmed you can go to any Planned Parenthood place for a medical abortion. You should abstain from sex in the mean time or your partner has to use condom.