No period, no positive

My husband and I have been actively TTC for about 4 months now. My period has been extremely regular and has actually been spot on with my app. My period is now 10 days late but all of my tests have come out negative. I was just wondering how long it can actually take to get a BFP or should I be worried about something being wrong? I have never missed my period before except when I had my first child so I'm pretty nervous...