Wondfo pregnancy test strips

This is my first month using wondfo pregnancy test strips (I've used first response previously). Does anyone know how soon the wondfo tests show positive? With first response I got a bfp a few days before af was supposed to show. It ended up being a chemical. I'm due for af Friday. So far all I'm getting is bfn but have breast tenderness (only in one breast tho) and slight cramping which I dont usually get before af. Also I've been exhausted (I actually fall asleep which is usually a nightly battle for me). All this makes me think I'm pregnant but the waiting is killing me and so are the bfn I got this morning. Any idea on wondfo and its accuracy? Thanks!