What Causes Vaginal Discharge With A Foul Smell?

hello,i noticed a negative change in my feminine odor in the last few weeks. I recently completed zythromax and noticed discharge accompanied by a foul odor which coincided with the completion of this antibiotics. I have been on various antibiotics recently because of a tooth infection. I have also been experiencing what feels like gas bubbles escaping from my vagina. What could this be?