Had this to, also went and had a early reassurance scan and all was okay. Your cervix can be easily irritated from things like sex etc which sometimes can cause a slight bleed. I think as long as it’s not like heavy and bright red period style blood it’s all very normal and common.
I had similar at 6 weeks. I left a voicemail with my local midwife team and they booked me in for an early reassurance scan the next day because I had a bit of cramping too. They said it was just delayed implantation bleeding. Always best to get checked.