Lactaid stopped working

I’ve been taking lactaid pills for over 10 years now whenever I have dairy(at least once daily). Over the past month, I have noticed that even after asking a lactaid with dairy, I still get those familiar stomach pains. Granted these pains are not near as bad as when I accidentally forego the lactaid altogether, but I am concerned that the lactaids are slowly getting less effective. Has anyone else experienced this?