Been on Clomid (clomiphene) for past 3 cycles. First two cycles were fine. Last one was only 4 days and spotting, dark, clotty, brown. Took a pregnant test, was neg.?

Thin lining? The longer a woman takes Clomid (clomiphene) the greater the chance it may thin her uterine lining. A period after having a thin lining can be lighter and lesser than it was before.
Clomid (clomiphene) for 3 cycles. The half life of Clomid (clomiphene) in the body is about 6 weeks. If you take Clomid (clomiphene) for 3 cycles continuously in the last cycle you may not respond. If you don't ovulate then your menses maybe abnormal! i suggest that if your not pregnant (assuming that you have confirmed ovulation at that dose) take a break after 2 cycles, and if you don't conceive spontaneously resume Clomid (clomiphene) again.