the best thing for u to do is to see a doctor as soon as possible.it can be an std, as well as bacterial infection. get a full std check up,and bloodwork. question? do u used comdon while having sex?
It could be an allergic reaction, but I think you should get this rash checked out by a gynecologist as soon as you can to find out what is going on. The "fishy smell" and discharge you describe sound like bacterial vaginosis, but only a doctor will be able to tell you. Do you have any blisters or bumps?
Best,
Em