Confused

The last day of my period was June 9th, my fiancé and I were intimate on the 11th. This app predicted that my peak day was the 17th but by the 17th I was spotting a little and experienced mild cramps. I wouldve just thought it was left over menstral blood but I also experienced some moodiness, nausea and body temp changes. I did some research and most sites say its too early to say that the spotting I experienced was implantation bleeding. I took an ovulation and pregnancy test, both were negative.