STD or infection?

This is kind of embarrassing to talk about, which is why I'm gonna ask here before I go to a doctor or something. But I have this really strong smell from my vagina. It's kind of fishy, and It's really strong, I can even smell it when I have pants on and sitting down. I recently had unprotected sex, but I asked him if I should get checked for any STD's and he said he didn't have anything. Could it be an infection or something? Or should I test if I have chlamydia or anything? I also get a lot of discharge which I think is where the smell comes from.