16 weeks and bleeding tmi

I'm 16 weeks and 1 day. Friday the 18th I had a good amount of blood when I went to the bathroom and wiped. so I went to the er. they did an ultrasound and baby was fine with a good heartbeat and my cervix was closed. I didn't have much bleeding the rest of friday. Saturday the 19th I have little bleeding but a very small blood clot. what could this mean? am I going to lose my baby? I have an app. on Monday but I'm freaking out. the Dr. said it could be bleeding because my uterus is stretching and it could have torn. has anyone gone through this and still had a healthy baby?