First real ultrasound tomorrow

Cassandra • -Son born 5/9/13 -Daughter born 8/16/15 -currently pregnant w/baby #3 (girl)
I am terrified!!!  I'll be 7wks tomorrow and just so scared of a repeat...back in July I was pregnant went in for early ultrasound and no heartbeat 
As we get closer to my appointment tomorrow I'm freaking out
Any that had a previous miscarriage and then successful pregnancy how dos you handle these first few visits?!? 
Please pray for me!