Help! Pregnancy test question

emily

So I’m almost 8 weeks postpartum and on our 6 weeks cleared we may have had an oops with unprotected sex. Fast forward to today I took a test and saw a faint positive, about 5 hours later I took the second test and can’t tell if I see anything at all on this one. Neither were fmu. Is it possible it’s a false positive ? Or why would it be lighter/not there hours later. Thanks