You never had a risk for HIV and did not need to test, but since you did, and all your tests have proven you were not infected (which was not even possible in the situation you described) then it is long past time for you to let this go. Educating yourself on how HIV is contracted would definitely help your anxiety.
you were not at risk for HIV which is why your tests are negative and will remain negative. can you define what you belive is HIV contaminated water?