spot omg after sex?

I'm 4.5 months pp and my husband and I had sex twice today. I'm still a bit tender where my stitches were but it's not horrible. Afterwards I noticed a had a bit of blood on the tp and in my underwear. A very tiny amount. Is it normal to bleed a bit now? Did I irritate the area? I don't feel like anything is wrong and I don't want to call the doctor over nothing. Anyone have any experience?