I posted yesterday about spotting

It went from brown to bright red and I went to ER last night. They literally did nothing and sent me home, so this morning I called my OB and she had me come in immediately. I had an ultrasound first thing. There is a “subchorionic hematoma” that is causing some problems. They said it looks like it will resolve itself but to keep an eye on everything and take it easy. I guess it’s a bleed/clot behind the placenta? I’ve never heard of this before. Does anyone have any knowledge or experience with it? I am terrified.