Yeast infection?

About to get oh so personal but I went to my obgyn and didn't get much help. I'm worried that something is wrong because I'm having a lot of white discharge that turns light yellowish as it dries and it has an unpleasant smell in my opinion. It also is slightly itchy. I'm not sure where to start in figuring out what it is but I'm very self concious about it and always paranoid it could be an std or something or maybe it's just normal. Do I need to go back to the doctor, how do I approach it? Thanks