TTC 1 year, semi regular, 12 days late but all negative tests.

Mary
Hi my names Mary I've been TTC for 1 year now with my fiance and we've had a miscarriage really early on, my AF usually comes around 3-4 days when expected but this month it's been 12 days since expected, yet the 2 tests I've taken have come back negative, any suggestion on better tests to use or what I should do? (Currently using regular clear blue tests)