All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
A woman knows that she is ritually pure after menses by one of two signs: (a) dryness of the vagina or (b) emission of the white discharge that women know as marking the end of their menstrual cycle.
Dryness of the vagina is when a woman inserts a piece of cotton into her vagina and it comes out without any trace of blood or yellowish or brownish discharges. There is no consideration to the white wetness, as the vagina is seldom free of it.
Therefore, if you perform ghusl (ritual bath) when you see this white wetness, then this means that you saw dryness, which means that the vagina has become free from any trace of blood or yellowish or brownish discharge. This is a valid purity, and you have to perform ghusl when you see it.
Hence, what you were doing, which is doing ghusl in this case, is valid, and you are not obliged to wait until you see the white discharge. Rather, you should perform ghusl when you see one of the two signs of purity. Whichever of these two takes place first, then purity has been achieved and ghusl becomes an obligation.
If dryness happens first, then you have also become pure and you are obliged to perform ghusl.
As regards the yellow discharge that you see after that, then it is not ruled as menses as long as it is not connected to the bleeding during your days of menses. So you just wash your private parts from this yellow discharge because it is impure, but you are not obliged to perform ghusl because of it as it is not menses. It is considered as menses only if it is connected to the bleeding of menses or when it happens during the days of menses, as per our view here at Islamweb.
Allaah knows best.