6w and 4d

Almost 2 weeks ago I had some light bleeding so they checked my HCG and it had doubled to 5016 in 2 days. On Wednesday we go in for an ultrasound, to make sure everything is ok. I had a blighted ovum in May, and this is the first pregnancy since that happened. I am just feeling a little nervous about it, any other women have a similar experience? I am scared that what happened before will be happening again. Any advice?