I guess miscarriage? 😔

Yesterday at 3pm I went to the bathroom and wiped brown blood it was followed by light cramping and everytime I wiped more brown blood. My doctor is out of town so I had to go to the ER. I’m suppose to be 6.5 weeks and when they did an ultrasound they said they couldn’t see the baby(maybe because I’m too early they said or something worse)but they could see the sac and it was in in right place. They also said because I had sex it could be from that. They said they didn’t know at this point and I need to come back Sunday for more tests because my levels will double then. All last night and this morning I’m cramping like a period and it’s a mix of brown with pinkish red blood, I guess this is the start of a miscarriage then... any advice or success stories, I’m so upset