Pace yourself when drinking so that you are metabolizing the drinks fully before starting a new one. If you still experience hangover symptoms the next day despite being sober, you may have an issue with metabolizing but probably aren’t allergic, since being allergic outright to alcohol would result in more immediate symptoms.
While I definitely agree that routine checkups like that should be happening (and especially for people who just got their licenses or are 60+) at least for a car dominant culture like the US I can see that being a huge burden both on safety organizations/DMVs and on the drivers themselves. :/