6 weeks, 5 days, no yolk or fetal pole, just empty sac...

I had cramping worse than usual today and called my doctor. I went in, she did bloodwork again and an ultrasound. Things just haven't seemed right, the only symptoms i've had are exhaustion and mild breast tenderness that just comes and goes. On the ultrasound there was a gestational sac measuring 6 weeks, 5 days but no yolk or fetal pole. My HCG was 536 on 4/17, 1,261 on 4/24, and today it was 1,531. She's thinking it's a blighted ovum. I don't know what to do. I can wait it out and see what happens, have a D&C, or take a pill to expel it. Has this happened to anyone else and the doctor was wrong? I want to still have hope that it will grow and show up. But i'm so depressed now.