Welcome to HCM,
As you are getting this white discharge frequently it looks like a fungal infection
. Usually these fungus are the normal comensal of the genitals which will be kept under control by the helpful bacterias, whenever there is imbalance in the environment these fungus will produces symptoms which you are having.
I would suggest you to take oral anti fungal and to apply topical antifungal
Regarding your sexual performance, it is mainly of your psychological condition, if you believe you can perform it will increases your sexual desire and performance.
Nothing is required to boost your desire , you are very young and you can perform. Take nutrious diet thats all, you donot require any medicines or any other remedies.