questions about period

Jessica

alright so my son was born in August of 2016 my last period before he was conceived was November 12th 2015 and my first after having him was December 5th 2017. I'm currently 5 days passed the day I was supposed to start my next one. I know I won't regulate yet but I also know me and my husband were intimate on and arround my ovulation cycle. when should I start to consider buying a test and seeing if it's positive or negative.