What is going on??

Based off my last period which was July 10 I’m currently 4 days late was supposed to

Start Monday I have taken multiple pregnancy test, been getting vvvvfl on some but still not bfp I’m not sure When I ovulated I’m just going off of my app which I think is wrong because that makes me 15/16DPO but I’m not sure yesterday I had brown/light pink blood in my cm but nothing eles today. Last May I got pregnant right after a miscarriage I implantated bleeding for a week very very light before then I was getting a negative test right after I got done bleeding I got a big fat positive. I’m thinking this is how this is gonna go if I am pregnant again. But I wish I knew when I overlighted but I don’t but I think my app might be wrong I’m right over later light or earlier so what do I do right now? Is anyone else in the same situation as me