It might be pinworms in your anus. The itching is abosolutely out of control. Parasites also give you that type of anal itch. They say woodworm tea is helpful. Parasites use you as host and spread throughout large intestine.
Pinworms are the most common worm infection in the United States. They are most common in school-age children.
Pinworm eggs are spread directly from person to person. They can also be spread by touching bedding, food, or other items contaminated with the eggs.
Typically, children are infected by unknowingly touching pinworm eggs and putting their fingers in their mouths. The eggs are swallowed, and eventually hatch in the small intestine. The worms mature in the colon.
Female worms then move to the child's anal area, especially at night, and deposit more eggs. This may cause intense itching. The area may even become infected. When the child scratches the itching anal area, the eggs can get under the child's fingernails. These eggs can be transferred to other children, family members, and items in the house.
Symptoms
•Difficulty sleeping due to the itching that occurs during the night
•Intense itching around the anus
•Irritability due to itching and interrupted sleep
•Irritated or infected skin around the anus, from constant scratching
•Irritation or discomfort of the vagina in young girls (if an adult worm enters the vagina rather than the anus)
•Loss of appetite and weight (uncommon, but can occur in severe infections)
Not really sure what it could be. I would suggest seeing a new Dr for this issue.
Also you say you have unprotected anal sex...I would assume that it is with a partner who is also HIV+?