Hallow madam,
I have fully understood the situation you are in.
The condition when the sac is present but there is no embryo inside it is called as 'blighted ovum'. Naturally, the embryo being absent, such pregnancies do not grow and get aborted. If it does not get aborted spontaneously, it has to be terminated.
You are having blighted ovum. This
pregnancy will not continue. Now that you have started brown discharge suggests that the
abortion process has started few days back and it is that old blood now coming out. You should not wait longer now. Please report to your obstetrician and get the pregnancy terminated ASAP lest the risks of bleeding disorders and
kidney failure.
The pregnancy test remains positive for about a week or more after the baby is nonviable or after the abortion has started. Therefore, your pregnancy test is positive. If your
ultrasonography has detected empty sac (blighted ovum) no other confirmation is required. Please get the pregnancy terminated at the earliest.
Next time, you do have good chances of having a normal pregnancy. If you want to go to the root of the cause, you may get the chromosomal study of both of you.
I hope, you have understood the issue thoroughly and will take the due action promptly.