How can I tell if my cycle just off or if I’m having implantation bleeding

On April 3rd I had unprotected sex, bf that I been with for 4 years did ejaculate inside me, I was ovulating during the time we are not trying to have a baby, I use 3 apps to track my cycles to see which one is most accurate, how ever Glow and my IPhone health app says I should be on my period now and that I’m 5 days late, my Flo app says I should be starting my period now. The last 2 days I had some whitish discharge and even clear with some blood streaks in it nothing heavy super super light, today 4/26/22 I wake up go to bathroom nothing but some brown blood streak and nothing since so far is this possible implantation bleeding? I have taken test they have all said Negative? Is it to early to test or is my hcg not high enough if I am pregnant, if pregnant this be my second pregnancy, my 1st I don’t remember bleeding with her and my test showed up instantly.