AF or Implantation

Good morning i have been TTC for a month i stopped taking BC 4 months ago. Just recently my period became irregular when trying to concieve i was due to ovulate this month on the 1st instead i got a light period that lasted 4 days took a pregnancy test and negative .. so then 3 weeks later I’m getting another cycle me and my fiancé have been very active can anybody explain I’ve also been extremely tired and moody and tender breast please help