pp periods & mini periods?

Mags
So I had my dd last July. I got my first postpartum period at the end of December. About a week and a half later I thought I was having another period but ended up deciding it was just a heavy spotting thing because it only lasted a little over a day. Then I went 40 days before I had another period. I figured nbd, my body is just regulating itself again. Now here I am, about a week and a half since that second period and I started cramping and am bleeding again. Has anyone experienced this? It's just weird because all of my normal preperiod stuff was going on today (irritable, terrible/unfixable back and hip pain, bloating, cravings). I'm a ftm so I've never done this before and I'm just wondering if it's normal for this to be happening.