For 3-5 days, my vulva was itching but the discharge was normal, watery. Yesterday itching was almost gone but the discharge was a little yellow and like cottage cheese, odorless and more than usual. Today the discharge is considerably less. What is it? Whatever it is, is it getting better?

It sounds like a yeast infection. I would go and get that confirmed. You will need over the counter medication to cure it. It won't go away on its own.