2 negative tests, no period

Good morning everyone! I had sex on the 8th of this month and my last period day was on the 22nd of February. And in January my last period day was the 24th. I usually last 5 days on my period,  Glow estimated I was to have my period start on the 18th. Today is now the 24th and I have not startedMy bf did not cum inside me , he pulled out. I took 2 pregnancy tests(first response) in the afternoon yesterday and today first thing in the morning. Both came out negative. What could this possibly mean? I do exercise regularily sometimes twice a day and I have been overthinking this. There also has been days where my discharge comes out looking like a brownish dry blood color . Please comment