What do you mean by you were sick before your infection?

It's a head cold but I think that its starting to get a little worse. I did'nt have a full fledge head cold until tonight, which I'm starting to feel. I just wonder if the treatment has anything to do with it.

Well head colds are progressive and could also stimulate from sinuses, allergies etc... but any medicine your taking for the head cold can counteract with what your taking for the infection making things worse. But no matter well stay well hydrated especially if your on antibiotics which you should have been prescribed by a doctor

What treatment did you use?

I didn't go to a doctor because I have had two yeast infections before, like at least a year or more ago and I took monistat3 and it work so I just picked this up from the store. I never have went to a doctor for it, although I will be scheduling an appointment soon with a obgyn. Would the treatment interact negatively with nyquil?

No, that won't act negatively with nyquil. It's possible that your immune system was just compromised due to the cold. You really should see a doctor about this to get it treated properly. Monistat is good, but not always a cure. Diflucan, prescribed by your doctor, is much better.

Does having sex cause yeast infections? Especially when you have not had it in about a year?

Having sex, when not adequately lubricated, can cause irritation that leads to a yeast infection.

OK thanks so much for your quick responses!

Sarah, if you don't mind, could you please scroll down to the Answer box to reply? The comments feature does not work properly at this time. Thank you.

The best thing to do is talk with your doctor. Those medications should not counteract, but having sex is one of the leading causes of yeast infections especially with hygiene come into play