Miscarriage!?!

Got my BFP Jan 20th.. had my first ultrasound Feb 11th baby measured 7 weeks with a heartbeat of 150.. went to the ER on Feb 20th sac measured 6w5days but no fetal pole or yolk sac was seen at the moment. . Went today for another US sac was bigger , yolk sac was seen but said they couldn't see the baby.. nurse said I had to have miscarried but my HCG levels are really high still & I haven't had any cramping or bleeding.. drew my blood again today I go back Wed to see if my levels are going down or up or the same.. I'm so confused they can't give me a solid answer.. anyone who has gone thru something similiar?? I really don't knw what to do or think anymore! :(