What Does Heavy Vaginal Discharge Imply?

I'm experiencing abnormal vaginal discharge. I have a lot of it (varies from thick to thin) that also covers the vaginal walls. There is also a funny odor but it gets especially worse after sex (almost rotten). I've been checked for yeast, BV, and STDs, and all tests came back negative. I've NEVER had this happen before. I was also on Nuva ring for 2 months, but took it out. Could I still have a yeast infection or BV and it just didn't show up on a test?