Period after breastfeeding

After I gave birth to my son I got my period 6 weeks after birth and I was breast feeding . I stopped breast feeding and pumping when he turned 13 months. I got my period every month on time when i was breast feeding my son . Once I stopped it is starting to act weird last month it was 3 days late and now it is going on 4-5 day late no period I am not pregnant of any kind I took a test . Is it normal for my period to be in and out since I stopped breast feeding my 13 month year old son .