how long does hcg stay in body after birth

[kaywhitford]

I gave birth to my little boy at 22 weeks gestation on the 7/2/19. Me and my partner have been having unprotected sex from the 14th we aren't trying again but letting it happen if it is meant to happen. But im worried that if i did a test in a week or 2 and it came back positive i would become happy but worried that it could still be hcg from my little boy😖any advice?? Xx