First of all, you did unprotected sex around fertile days or close to the ovulation time as per your LMP. Bleeding with clots (small lump) around period due date mostly indicates implantation
Here, you need to undergo one blood test
for beta HCG
& TVS scan to rule out the product of conception if any.
After that, you can consult with your gynecologist for next line of management. Maintain genital hygiene properly, avoid stress
& take balanced diet.
Be well & take care.