In my opinion, when something is not right down there, like there is foul odor or if there are rashes and stuff, I don't think it's the time to be fooling around with self tests. How about going to the gynecologist for a check up right away?
to put it plainly, there is no home/self test for this. you will know once you have it. at least what you did to get you to suspect if you might have it, only you can answer that. and it's pretty obvious what it is.
is it itchy? does it feel like burning? trouble urinating? foul or smelly discharge? if you have all of the above, pick up your phone and dial your doctor. I think that should suffice for a home self test!