SPOTTING instead of period! TTC help

Caitlin
Hello all,
TTC I'm about one week late now and I thought I had started my period yesterday, but turns out I just had a little dot on my tampon and today too. Does anyone know what this means or if it's a sign of pregnancy or not? 
I have tested about a week ago and it was negative on a Clinical Guard test (not sure if I trust those), but nothing since then.