I am sorry about what you have been going through. I shall try and answer your questions in the best way I can.
1. You can have a positive home pregnancy
test even before you miss your periods.
2. A tilted uterus can make it difficult to see the uterus, especially on an abdominal scan.
3. However, if you can see the uterus on a transvaginal scan, there is no reason why you should not be able to see a yolk sac
or a fetal pole
. Also a tilted uterus does not impact measurements.
4. A diagnosis of a blighted ovum
can only definitely be made if another scan, a week apart from the first shows the same findings.
after a blighted ovum can take from days to weeks of diagnosis, and this is something nobody can predict. If the pregnancy is early(less than 6 weeks), it should not be very painful. However pain threshold varies from person to person.
I hope I have answered your queries.