OPK as Pregnancy Test?

So, I'm 7 dpo and I'm really hoping this is the month. We've been trying since October. I've been charting and tempting. It's looking good. I've had high temperatures after ovulation and a dip that looks like an implantation dip. I'm 7 dpo and got a bfn on a hpt. I have extra Wondfo opks, so I tried one. It had a faint pinky line. I've heard that opks can be used as hpts. Does anyone have any experiences with this?