1) It's impractical to test everyone for antibodies. There's enough empirical data to suggest that immunity wanes over time for most people that it makes sense to just give everyone a 3rd, booster shot. 2) It was always expected that vaccine immunity would wane over time. Nobody (of any relevant repute) ever suggested otherwise. 3) I don't doubt that you had side effects from the vaccine. But there's a strong probability that the side effects of an actual infection would have been much, much worse for you. You may potentially have an undiagnosed health issue that could have potentially been a comorbodity in an actual infection.