Implantation??

Hi i am so worried. My last day of my period was last saturday the 23 and we have had sex everyday to try to time things right. Well tuesday i started to bleed off and on a brown blood but pretty lite. It only show when i wipe. The spotting has been off and on since then but today i woke up extremely nauseaus with some cramping and bloating. I feel my mood is changed and i just feel something is not right. Could it be imolantation or a early misscarriage?? Anyone ever had this happen?