Has anyone else experienced bleeding?

Rebekah
I started bleeding a lot two days before my 13th week. And I mean A LOT.. I was scared to death we had lost the baby even though I had just experienced light cramps and not any major pain, but I was woken up in the middle of the night and the blood had soaked my leggings down to my knees. (I honestly thought I had wet myself in my sleep before I noticed it was blood) I went to the ER and the doctor even said that there was "more blood than he hoped and odds weren't good." But after an ultrasound we found out the baby was completely healthy with a perfect heartbeat.
However, I'm now two days before my 16th week and I'm still bleeding.. not as bad as that first day, but I haven't been able to go without an overnight pad for 3 weeks. My doctor isn't concerned at all, but I have not talked to anyone else that has ever dealt with this.