TMI ladies

I'm 30 weeks and 5 days pregants, and recently (maybe for about a week) I've been smelling this fishy odor from down below 😫 my boyfriend says he doesn't smell it, but i smell it all the time so i think he does too. I'm std free, can someone please tell me what could be the problem. My doctors appointment is next month, but I'm really tempted to go to the er