PLEASE HELP PLEASE.

Took pregnancy test om the 16th. Both positive. Went to er yesterday. Took a pregnancy test and was positive. They toom blood and everything. Doctor told me it was a threatend misscarriage and that my sac should show a 5 week old baby with a hearrbeat. He saw a sac but no baby and no heartbeat. My symptoms are fatigue, very bad cramps. Feels like I have the flu. I have no bleeding. My body aches so bad. What do y'all think? How am I suppose to have a misscarriage if there's no baby?