Hi Jade. Are you and your husband using condoms, toys or lubricants?
An allergy to something that is touching the affected area could be the culprit. If you are pretty sure there have been no new exposures, then it is more likely infectious. Have you had a complete gynecological exam during this period of time?
The easiest way would be to go to a nearby express care or urgent care clinic. They can check your urine and do an abdominal and bi-manual exam and culture any discharge. This will guide the appropriate treatment, and get you on the path of feeling better.
You're welcome. Hope all works out for the best.