Claudia? Sorry, chlamydia
So, see your doctor. Incidence of any symptoms of Claudia in women as well as gono are low / often lacking in any symptoms. I guess you can also have an itch but with 9 years here, that is not commonly reported. Herpes sores appear but what you describe does not sound like an std from my perspective and experience. :). You've tested negative as well. It is important to adhere to window periods for testing though. I would suggest seeing your doctor again and you can make sure you don't have an std and explore what else is causing this if you are again screened negative. I do agree that yeast infections are very common. And discharge doesn't always follow what you expect. The only way I knew I had my last one was the telltale sign of itching. I didn't have the typical discharge. I wish you the best.
STD's really don't itch. I'd not be worried about that. If it were me, I'd see my doctor and have my discharge swabbed. Your discharge may not be typical and you still have yeast. If not, they can talk about other ideas of what is causing the itch. Could be another type f fungus than yeast. Could be dermatitis. You could try vagisil wipes to see if they help. But I'd get checked out by the doctor.