3 weeks of spotting

I have only ever experience spotting when I was around 6-8 weeks pregnant with each of my three children. So three times in my whole life.

Currently, I'm five months post birth (have had three complication free births) and I've had random spotting on 5 separate occasions over the last three weeks. Nothing consistent, no actual bleeding, just blood coloured discharge when I wipe(sometimes a little colour on my underwear).

Is this normal? Should I be worried? Should I be taking a pregnant test? I'm so confused.