Hello all! I’m sorry if this isn’t the right place to post :/

So I use two <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period apps</a> to track my cycle and use an average of the two to prepare for my period. Well, AF is currently 3-5 days late (was supposed to start July 16-18). <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> tells me my fertile window started June 29 and Clue tells me it started July 3. So that makes me 14-18 dpo if I’m calculating correctly? I’ve taken 2 tests but both were negative. My period ALWAYS comes within the predicted time between my two apps so this is very abnormal for me. Is it too early for anything to show up on a test?