Help!!!...I'm Nervous!

DC

.....I went to the doctor at 5w2d and the u/s just picked up the gestational sac....no yolk.....should I be worried?....my ob told me we have to see if the yolk will form but I'm losing my mind!!!.....I'm thinking about making my doc appointment for 7weeks instead of 8weeks!....I'm currently 6w5d and I'M LOSING IT!!