Bleeding/Spotting Question

So I have been having what I consider bright red bleeding/spotting the last few weeks. It is very runny blood that starts when I use the restroom when I wake up and basically stops after that. I will spot the rest of the day more of a brown blood, but nothing else. The strange part is that it's like clockwork, every 6 days I wake up to it. I went to the doctor the first time I had it and they didn't see anything abnormal, the second time I went to the ER. Again, nothing abnormal found. And I've had two episodes since. Each time we have seen a healthy heartbeat, and I just had my 8 week scan earlier this week and everything looked perfect. Has anyone else experienced this? It freaks me out. But I'm being told I'm a "head scratcher" for this bleeding...