Force miscarriage or wait it out (continued)

LMP-3/17/15

 hpt- 4/16/15

First hcg-4/17/15-43

2nd draw-4/20/15-109

3rd draw-4/27/15-2522

4th draw-5/4/15-10,000

So my levels didn't double the last one. Based on my lmp, I should be 7w1d today. 

I went for my first US yesterday and all they saw was a sac, no baby, yolk, or heartbeat. The doctor said its most likely a blighted ovum. He suggested a d&c but I said I wanted to get my blood drawn again just to make sure. Which I'm doing today, I'll know results tomorrow.

The new info- I called my doc today cause I realized the US tech never told me what the sac was measuring at. My NP told me I'm measuring at 6w1d almost a week behind. So my question is, did anyone have this situation or maybe got an US around 6 weeks and saw nothing but went again a week or two later and saw something?? I know I'm stretching this hope a bit much, but none of this makes sense to me! And my levels are doubling every 3 days which can also be normal. I just need something to keep me a bit sane until I know more. Thank you.