help! Trying to conceive... 1 positive pregnancy test and 2 negative tests

Hello

Wondered if this had happened to anyone - I took a non-digital test this morning that is showing a very faint line and I went to buy two more tests (I did them both I know I should have waited) but both said not pregnant (both digital tests)

I am 3 days late on my period and have been googling and it says to wait 48hrs for the HCG levels to rise to test again? Has anyone got any advice or any pregnancy tests they found more affective?

Help! Trying to not get too excited