So frustrated!?

Marissa

So last night I get home from work around 4am, and I test (I've been testing for about a week now, nothing.) And I get this test (pic below) with a line I can obviously see but is very faint still. Glow said period was late by 3 days as of yesterday. Ovia said period should have started yesterday. Then this morning I wake up to AF. Why would I get somewhat of a line right before AF?!