Second postpartum period is late- Negative test?

M

Hey everyone, I had my first postpartum period at 19 months postpartum and it was over Christmas time. I am on cycle day 38 and still no period. It is normal for me to have a cycle length anywhere from 30-34 days. I have tested and it's a pretty solid negative. Is it common to have one postpartum period and then not get another one for awhile? I am still breastfeeding but only a few times a day and at night. I work full time and don't pump for those 8 hours either. We use the pull out method and know it's not super safe, but we did have sex several times around my predicted ovulation time. I'm just wondering if it's likely that I'm pregnant even though my period is around 5 days late and the tests are negative? This was my test from this morning. Anyone have experience or insight? Please encourage me that missing a period while having negative tests is normal lol!