Fear- blighted ovum?

Had some spotting this week that yesterday became faster red spotting, though still not a huge amount it was enough to full on freak me out. Went to the ER to get checked. I'm supposedly 7.5 weeks but was not going to see a Dr and have an ultrasound for two more weeks. Long story short, I got an ultrasound and all they could see was a sac. Tech said it looked like I couldn't be more than 5 weeks, but I had a BFP just over 3 full weeks ago (BFP when my LMP was 4w3d) .

Then my bleeding slowed to a light brown spotting again. ER sent me home only knowing that it's too early to see baby, and at least it's not an ectopic. I've 11 days until my originally scheduled first full Dr appt and ultrasound. I've only met with the nurse at my OB office so far. I'm going to see if they can see me earlier but I'm also just totally freaked about the possibility that maybe pregnancy just isn't viable and for whatever reason I simply haven't miscarried yet.

Just needed to put it out there to get it off my chest a bit I guess.