Periods and breastfeeding help

I’m a first time mommy. My periods have been very regular, well were before baby. But. I missed my period this month. I am exclusively breastfeeding at the moment. I’ve had I think two periods (light spotting in December, full period January) since I had my daughter in August. So this month I’m late according to my app by 6 days. Now I have been breastfeeding more with my baby since I have been home more where as when I got my last two I was only pumping bc i was working 50 hours a week. I’m not sure if that makes any difference. But my question is. Breastfeeding mommas were yalls periods irregular or stayed the same after baby? Does breastfeeding alter your periods at all. I’m concerned I may possibly be pregnant. I’m taking a test tomorrow bc I’m freKing out