Why are my lines not getting darker!?!

So yes I'm that crazy woman that tests every day to see if my lines are getting darker. I got my vvvvvfl three days ago and it's still not much darker. I want that blazing no questions asked line but it doesn't seem to be happening. I had a missed miscarriage two months go and two afs since. My af this month is due Monday but I'm scared she will come. Anyone have any insight? Thank you! Please don't just say must be a chemical either 😢