Pregnant or Not !?

Hola- Quick background: My fiancé and I are trying to conceive. We have had unprotected sex 5 different times and two times right before my ovulation day. I took a pregnancy test one day before my expected period and it was a negative, but now i have missed my period (which was supposed to start the 9th). I have been having real light cramps, and normally i cramp horrible the first day and have a heavy flow. Today i noticed a light brown possible pink "discharge" / discoloring when i wipe, but no actual blood or how my cycle normally is. Could this be possible implantation bleeding? Should I wait a week for another test? Is this normal?