You need to go see a doctor but from what you are saying you have a UTI or a yeast infection. You need to go get some medication to treat it.
It is very normal for the body to do this, even before you have had sex. Sometimes, the vagina produces discharge to clean itself out, even if the only substance within is your own sweat. I would only go to a doctor if the discharge changes color or consistency, or if new symptoms show up. I hope this helped!