For me, my test didn't show positive until 3 days after my period was supposed to start.
I used a clear blue digital test and it showed positive 4days before my period was due.
Are you breast feeding? I hear you usually wont have periods until you stop breast feeding
I would just wait to see if you cycle again. Sometimes it takes up to six months before your cycle returns to something you might consider normal. Be patient and just take care of yourself and new one in the mean time.