Hallow my friend,
If you were otherwise having regular menses throughout your life, missing a period for one week should be considered as pregnancy unless proved otherwise, particularly when associated with nausea and sore breasts.
Then started brown bleeding which suggests that the pregnancy was non viable for some time before it started aborting. Could be that it was a
blighted ovum (cyst without embryo in it). Then the bleeding started with
abdominal pain rather heavily with orangish flow.
Yes madam, I do agree with you. This is most likely to be
miscarriage. However, get it confirmed by reporting to the Obstetrician.
Urine pregnancy at this stage will be misleading.
Ultrasonography may be of some use. At least it will reveal whether the abortion is complete or incomplete. In case it is incomplete, you will have to undergo evacuation to get it completed.
Also since you had pain in the ovarian region, you will have to get ectopic pregnancy (pregnancy outside the
uterine cavity) ruled out. It is a condition which may land up in bleeding emergency and hence needs to be handled well in time and ably.
I hope this guides you for appropriate steps.