I have had bleeding in many of my pregnancies. Some didnt fair too well, but there was an explanation, and were unrelated to the bleeding. In 3 of my 6 pregnancies, I had low progesterone. This was diagnosed with my blood work, and easily fixed by taking supplements until the end of the first trimester.
Then in one of my pregnancies, I had a hematoma. What it is, is a collection of blood behind the placenta, that is usually caused when the baby implants. The baby burrows in deeply, diplacing some of the uterine lining (which is implantation bleeding and occurs about 7-14 days after conception) but sometimes when the baby burrows, they will bruise the uterine wall slightly. Then as they grow, the bruise either heals and reabsorbs, or bleeds out to heal. This will be detected by ultrasound, the progesterone detected in bloodwork.
Though I have had miscarriages, the pregnancy I bled the most in was a healthy baby! So while seeing blood is scary, it doesnt always mean something is wrong. Hang in there!