yeast infection?

hey guys, I think i have a yeast infection. my vag burns a little and it itches sooo bad. and its not any std, I know that for a fact. I've never had a yeast infection. it's so uncomfortable. I was thinking that my panty liners were bothering it, since I've been wearing them frequently. (heavy discharge, not cottage cheesey, I just have really heavy discharge, my gyno said its just cause I'm 15.) but my liners have never really bothered me before. but I haven't worn them so frequently. help?