Pregnancy test confusion

Mel

I have done two basic pregnancy tests that have blue lines (I done one yesterday and one today, both have lines) but when I done the more complex test that shows how many weeks you are that said “not pregnant”. Could it be that it’s still too early for the more complex test? Period is due in 3 days and I’ve had light bleeding/spotting which I believe to be implantation bleeding. Any advice would be gratefully recieved