Yeast infection??

So I’ve been having a very itchy/uncomfortable feeling since 2 days ago down there. My period is late and I’m not sure what’s happening? Also, today I noticed my discharge to be yellow/green. I’m probably not pregnant since I always use condoms with my boyfriend, but I’m not on any bc. Do I have my first yeast infection and if I do how long will it last? I can’t go to the doctors so will it go away on it’s own?