Absolutely Terrified

So last month I missed my period, and now I'm afraid I may be a little late this month. I just went to my doctor's today, and he said I have a yeast infection. Nothing too bad, but he gave me three pills for it, that I start taking tomorrow.
I'm freaking out, and maybe it's over nothing, but why/what's making me miss my periods?! Should I be blaming the yeast infection?

I also have PCOS, and am on birth control (Apri 28), and as far as pregnancy goes, I took two pregnancy test, each test was 10 days apart. Both were negative.

Thanks so much.

[AnnieBrooke]

PCOS would be a more likely reason.  A yeast infection does not delay a period, as periods are up in the uterus and guided by hormonal signals from the brain and the ovaries, they don't originate in the vagina where a yeast infection is.