Symptoms I’m having

Kirby

I’m 5 days late, having some back aches and spotting started off pink & now is a brownish color. Usually when me and my spouse have sex i automatically start my period if it’s almost time. That didn’t happen. Instead I’m spotting 3 days later. I’ve had pregnancy test that are negative and faint positive. Not sure if maybe I’m just late but I never really just spot it’s usually me waking up to a full blown period 😑. Opinions?