7 week ultrasound, no fetus.

Does this mean I'm miscarrying? Doctor hasn't talked to me about it yet because we had to go somewhere else for scan. Radiologist says it's a chance that it's a blighted ovum but says there's also a good chance that I could still be carrying since gestational sack still measures 7 weeks and is current to where I should be. I don't want to give up hope because last year when we saw the sonogram, we knew we lost our baby with the heart beat. Doctor has also told me that I have a tilted uterus, could that also be a reason we couldn't see it?