No period with Nexplanon

Hi ladies! I got my Nexplanon implant a little under 2 months ago and since then my periods have been much lighter. However, my period this month hasn't come on time; I'm only two days late and I know that changes in your menstrual pattern are common with the implant, but should I be worried?
As far as other forms of birth control, my SO and I never use condoms but he's very good about pulling out in time. 
Thanks everyone!