6 weeks and no heartbeat

Ok so I went to my ob today they did an ultrasound as me and my husband are high risk for twins but there was no heartbeat at all.. she said to come back next week so we made that appointment I am trying not to be concerned but it hit me hard. She thought it's to early or miscarriage and this would be my first ever miscarriage of it happened. How should I feel besides non stop crying? What should I do?