By the sounds of it, you have a yeast infection.
Is it thick and white, like cottage cheese? If so, then it's a possible yeast infection. If this is your first yeast infection, I'd get checked out by your doctor.. possibly an OBGYN. They'll do a test, and if it's positive for a yeast infection, then you'll get either oral medication or a couple of gel pills you gotta insert into your vagina.
If you're wanting to test yourself, at home, then you can.