bacterial vaginosis

I'm 15 weeks pregnant and two days ago I had really bad back pain and cramping felt like I was having contractions and I started bleeding heavily. I soaked two pads. I went to the er and they did an ultrasound and baby was doing great. Heartbeat was good. They told me I could have a hemorrhage but to follow up with my doctor. I did the next day and was diagnosed with bacterial vaginosis. The bleeding has stopped since yesterday but just now I noticed I had a small dark brown clot. I took a shower and noticed another small one. I'm so scared right now. Has this happened to anyone else?