Spotting? Feeling frustrated...

My AF is "due" today, but.... Yesterday morning I woke up, went to the bathroom and it looked like my period started. Bummer :( so I put in a tampon and went on with my day. A few hours later I changed my tampon... Even though there was hardly anything on the first one. When I took the second one out a few more hours after that... Not a single drop of blood. I've had no cramps or any of my usual period feelings. And no bleeding since yesterday morning. I took 2 tests this morning... Bfn. Anyone know what I experienced yesterday? Why the blood? Why did it stop so suddenly? I'm trying not to get discouraged but it's hard to stay positive sometimes :/