HIV symptoms or Noracin effects ?

Hi, welcome to the ehealth forum and I am glad to help you.
You seem concerned if you have acute HIV infection after risk exposure(homosexual exposure) about 18 days ago.
Acute HIV symptoms generally occur within 2 to 4 weeks. The most common symptoms are fever, fatigue, and rash. Others include headache, swollen lymph glands, sore throat, feeling achy, nausea, vomiting, diarrhea, and night sweats.
Your symptoms of loose motions and diarrhea day after risk exposure could be due to tummy bug but the tension and scare that you are going through can only be relieved by HIV testing as early treatment of acute HIV infection can delay the progress of disease. The normal HIV blood test will come back negative for someone who was infected very recently. The test looks for antibodies produced by the immune system to fight HIV. It can take two months for these antibodies to be produced.
However, the viral load test measures the virus itself. Before the immune system produces antibodies to fight it, HIV multiplies rapidly. Therefore, this test will show a high viral load during acute infection.
If you think you might be in the acute stage of HIV infection, tell your health care provider and get tested. Talk to your health care provider about the possible advantages of starting ART during acute HIV infection.
Hope this helps. Take care.
Note: This post is not to emphasise final diagnosis as the same cannot be made online and is aimed just to provide medical information and no treatment suggested above be taken without face to face consultation with health care professional.