Thanks for the query,
clomiphene ( Clomid ) is a selective estrogen receptor modulator
Common side effects of clomifene include: hot flashes, abdominal discomfort, visual blurring, and reversible ovarian enlargement and cyst formation.
Infrequent side effects include: abnormal uterine bleeding
, nausea, and/or vomiting.
So your symptoms of passing large clots with gray tissue is one of the side effects of clomiphene.
It is not due due miscarriage
as pregnancy test is negative.
Anyways, continue taking clomid next cycle, Reduce weight if overweight
, eat healthy, and exercise moderately.
Hope this helps,