drop in bbt -- help please!

I know I am not supposed to be temping, but I have an Ava, which can be worn and <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">track pregnancy</a> symptoms too. My temp has dropped A LOT over the last two days, and is very close to my coverline. I am well-aware of what this could mean, but we have had so many losses. Any stories of hope? I'm desperate. 
(No bleeding yet, btw, and I am 4 weeks today.)