I have the same problem. It's because of a rapid hormone change. I was getting them every month (especially if I had intercourse around that time). I had a pap come back irregular and had pre-cancerous HPV (human papiloma virus) which is carried by 70% of the human race, so if you have it, don't feel "dirty". People with HPV are more succeptible to yeast infections. I had to have surgery to remove the pre-cancerous growths, and have found that taking Acidophilus twice a day has gotten rid of any yeast infections. If I stop taking it (which I did when I got pregnant in June) the yeast flared up again. MY doc said it's o.k. to take during pregnancy, so I haven't had any problems since I started again. After you take it twice a day for a while, you might be able to wean yourself down to 1x/day.
Good luck