Period

Hi mummies. I gave birth in the first week of December 2019 and got my first period on the 3rd week of January. And then I had sex with my husband the day before my next period cycle without protection. Is there a chance I might be pregnant because I am 6 days late? but I also know that some women's menstrual cycle is irregular after birth. I have yet to get a PT kit because I am afraid of whatever the result will be.