Hi Doctor. From Past Some Days I Have Been Noticing

Hi doctor. From past some days i have been noticing a foul smell discharge like an egg. Its quite smelly but white in color and very rarely greenish. But i have no cramps, neither its ichy nor i burn while i pass urine. It stopped in between for few months but has started again these days. Its definitely not an std as i had my tests as well.. But still if something serious is going on..! Tensed!
Please support me with an answer. I'll be highly obligued. Thanks.