Leaking discharge

So i a couple months ago i slept with this guy and i don't know what happened but ever since then I've had discharge every day to the point where i have to change my underwear i went to planned parenthood and got tested and they all came back negative but i still have A LOT of discharge and i don't know what to do because it itches really bad sometimes and at this point it's just annoying and irritating. What should i do?