hcg levels

Hailey

How long did it take everyone's hcg levels to return to zero after delivery? I had a c-section on May 31st and took a pregnancy test (just to be safe) bc I was gonna drink a little on the 4th. After about 5mins, a faint second line showed up. I've had sex with my husband twice since I've had my daughter and we used protection both times. Could it be left over hcg or am I pregnant again?