Finally, your symptoms do not suggest a new HIV infection, which does
not cause gastroenteritis
as the only problem; as you seem to know, you didn't have any of the usual symptoms of ARS.
But most important, your negative test results, especially the one at 7 weeks, prove you didn't catch HIV. A negative rapid test, either fignerstick or oral fluids, is just as reliable as a lab-based test. Something other than HIV is the cause of your gastroenteritis.