STILL NO PERIOD

So this was my fourth child, fourth pregnancy. Each pregnancy postpartum my bleeding stopped at about 2 weeksish. This pregnancy it didn’t stop for 3.5 weeks. I only breastfed for 2 weeks. I ended up stopping because of acid reflux and I it was very frustrating for me to pump hold a newborn and care for a 1 year old. Anywho my first period would have came by now. With my 1 year old and previous babies it came like 6 weeks pp. yes I’ve had interviurse I took a test two weeks ago it was negative.. this pregnancy I bled during labor a lot more then I did with the others! For the past two weeks I spotted randomly brown blood not even enough to wear a panty liner. Any input?