I would start a new thread if you can, you may get more answers.
Sometimes you can get implantation bleeding or just old blood in the uterus.
Speak with gp as you may have had a miscarriage but still retained product so they may send you for bloods for your hcg. I tested positive for 9 weeks after my miscarriage
Or maybe self refer to the midwife as you would be far along enough for a booking appointment and they will check your bloods.