A little insight needed!

Na
So, according to my glow calendar, I missed my whole glow period. And usually the glow <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period tracker</a> is almost usually right, either a day or two off. But it says I missed my whole period. And on the 23rd (the day glow said I should have ended my period) my fiance and I had sex, and I started bleeding. I thought that I had started my period so I put a tampon in, but when I had taken it out to change it, there was absolutely no blood on the tampon. And there has not been any sign of a period since. I haven't taken a pregnancy test yet, I might just wait a little longer. I just need some advice or help.