Seems like it may be a yeast infection - those are very itchy. You'll need to see your doctor to get tested. They will just need to take a sample of vaginal fluid and look at it under the mircoscope. You'd know something right away. Whenever i've had a yeast infection i've taken diflucan and used something like vagisil for the external itching.
Just take a deep breath and go to the doctor...You'll feel a lot better once you do!