Bleeding 22 weeks

So last night when I went to the bathroom, alot of bright red blood came out. I am 22 weeks pregnant with my 2nd child and I never experienced this in my first pregnancy, so it scared me. I went to the emergency room and my cervix was closed and my babies heartbeat was perfect. I went to my doctors office for an ultrasound this morning to get the placenta checked, and everything was fine with that as well. She told me they couldn’t find the source of the bleeding and prescribed me macrobid and bedrest for 3 days. The bleeding stopped all day until just now when I went to the bathroom. There was a glob of bright red blood and now I don’t know what to do or think. Am I going to be okay?