I'm only on them once a day. I've had no color changes, but then again I haven't been spotting. It's probably completely normal and just spotting, but why don't you call your doc tomorrow and ask?
The suppository may be irritating your cervix. I wouldnt worry unless you have bright red discharge.
I feel for you, progesterone suppositories suck! I was on them with my last pregnancy. I took Crinone 8% at night from weeks 5-10.
While I was taking it I did get some brown, even sometimes pink discharge. The Dr. said this was OK, it might just be irritating my cervix and to make sure I am not putting the applicator up too high.