noticed a white residue in my vagina

Could it be a yeast infection? Have you ever had one before? They have those testing kits at the drugstore that you can use to see if that is what you have. If it comes out positive, buy some over-the-counter medicine at the drugstore for it. If it doesn't go away after you've used it for the full course (3 days or 7, depending on the one you buy, follow the directions closely), then you should make an appointment with your gynecologist.

Also, good job using a condom! It seems that so few people on here do (usually leading to trouble) and it's so nice to hear someone say that they did.