Started to bleed at 14 weeks pregnant?

I'm 14 weeks pregnant and everything has been fine so far with this pregnancy. Well, yesterday afternoon when I went to the restroom and wiped there was a good bit of pink blood on the toilet paper. I immediately called my doctor and she had me come in and she checked my cervix and she said it was still closed and she did an ultrasound on the baby and all was fine..heart rate was 162. Baby was movin and groovin in there...=) So she tells me that she thinks everything is fine and sends me home. I'm still having the dark pink, light red bleeding..only when I go to the restroom and it's only on the paper. So my question is..has anyone gone through this before and if so what was the outcome? I've got 3 children already and I never bled with any of them. Thanks in advance for all of your answers. =)