Thanks for your question and concern. It is quite a common thing to get confused about the tests and all. It sounds like your doctor thinks it unnecessary to get you tested for HIV. If he thinks you are at the risk of HIV, then he would surely get you tested for HIV.
HIV stands for human immune virus. It mainly transfers through the exchange of the body fluids such as the semen, blood, the vaginal fluids, menstrual blood and also through the breast milk. If a person is affected by the HIV virus then the HIV virus has got into the blood stream of the particular person. HIV virus cannot travel through the air like that of the flu virus or like a common cold or even through intact outer skin.
The sexually transmitted diseases can be easily transmitted from an infected person to another person through the skin contact itself. That is why your doctor took the tests for sexually transmitted diseases and not for HIV. If you want the test details of the tests you have undergone then you could call your doctor or visit him and ask for the explanation.
The HIV is contained in the precum, but usually the precum is a very small amount of the fluid and usually it will dry very quickly during the air contact or on the skin. HIV virus is not at all capable to live on the outside environment. It die very quickly once it is outside the body and also it cannot be transmitted at all if the fluid it is contained dries off. So you have to be reassured that the chances of the HIV virus to be transmitted by the way you told is minimal.
The HIV is mainly transmitted during the time of unprotected sexual intercourse, which includes both the anal and vaginal sex. So the best way to control this is by the usage of condoms during the time of penetrative sexual intercourse. Condoms are easily available and are easy to use. Also it is advised to use dental dams during the oral sex. Oral sex contains both the contact between the vagina and moth and also the contact between the mouth and penis. Sexual health is an important thing to be taken care of.
If you still think that you have been affected by the HIV, then you can get it tested it at the local genitourinary medicine (GUM) clinic. All the tests will be done in confidential. So you need not to be worried whether anyone knows it.
Good luck.