You really have no choice other than going to doctor. No one on the internet can give you an accurate diagnosis. We can only guess, and there are literally hundreds of possibilities. That won't help you, you need a diagnosis, and a treatment. Only a doctor can give you that.
I know it's embarrassing, but I can assure you that it's not as bad as you think it is. For one, the doctor is only looking at you from a medical perspective. Trust me, he/she sees millions of patients a day. Okay, not millions, but a lot!
It will be quick, and doctors are professionals, you won't be made to feel uncomfortable about any aspect of this.
Like WG suggested, maybe a female doctor would be better for you. I myself prefer a male doctor. I figure that a male doctor is more gentle than a woman, because he doesn't know what being female feels like, so he's extra careful.
Either way, you need to get this checked. Tell your mom, and she'll book the appointment. She can even stay in the room with you if that's what you want.
Don't play around with your reproductive health, it's not something you should ignore. It could be something as simple as a rash, or an allergic reaction, but it could be something serious. The sooner you find out what's going on, the better.