Baby's heart

So I just got a call from one of the nurses at my Dr office to tell me that I passed my 1 hour glucose test but they want to schedule another ultrasound to look at the baby's heart in 4 weeks but I just had an ultrasound an hour ago cause they couldn't see all 4 of the heart valves at the last ultrasound idk what to think I'm freaking out and I have no of clue what's going on and have to wait till next Thursday to talk to my Dr