I'm sorry you're dealing with this especially at such a young age. It's good they are going to do some blood work to check for an endocrine problem. Problems with the thyroid, pituitary or adrenals or some other endocrine gland can affect every cell in the body. Hoping you get answers and treatment to address the underlying problem. Let us know what you find out.
You are young to have this. It's much more common in menopausal age women. The usual cause is low estrogen levels which cause vaginal walls to thin. What is your doctor's solution for this? Are they doing hormone checks on you to see if you are imbalanced? Do you have regular menstruation?