Hiya Jim. The tests are FDA approved. Their for, you should have no conerns on that front.
The fact that all 3 tests came back negative and you last test was over 3 months, means your results are certainly conclusive. Your HIV negative
Rapid HIV tests are as reliable as lab-based tests.
Why? Because rapid tests are one of the biggest achievements in HIV prevention. It was assumed that people would not test for HIV because they could not wait 2 weeks for results, and in fact, many people who did test with lab based antibody tests, would not come back for their results (becuase they couldn't face the news).
So a rapid test that is FDA approved MUST be as good as the tests used in labs. You've had three of them, 8, 12, and 14 weeks. If there was ANY chance of a false negative (and there isn't especially since you tested outside the window period) then you are safe.
Rapid tests are used widely and predominently in Africa where HIV is more common. If the tests were not reliable, they simply would not use them.
Further testing is not recommended. If you do decide to go for a lab-based test, you can expect a negative result.
You are HIV negative. Accept it. And best of luck.