Welcome! I hope you find your experience here what you need it to be. I think for most people that's usually the case.
As for phenobarbital, to my knowledge it's pretty much the sole survivor of the barbiturate reign. Everything that barbs were once used for has now been almost completely replaced by the benzodiazepines. The reason is that the benzos are not only just as therapeutic, they are often more so, and much, much safer. Barbiturates like secobarbital, amobarbital, pentobarbital were all quickly lethal if taken in excess. Benzos, OTOH, when taken without the synergistic uses of any additional CNS depressants, rarely if ever cause death from overdose.
But phenobarbital is still around, yeah. It's used mainly as an anticonvulsant, and works especially well when it's used in tandem with another anti-epileptic like phenytoin. It also has its anxiolytic properties, but at the end of the day its anti-anxiety effects are inferior to many more modern drugs, starting perhaps with the benzodiazepines. Also, its potential for abuse pales in comparison to the barbs which are no longer prescribed, as its onset is slow and somewhat "murky", compared with fast and seemingly powerful.
I think the complete range of barbiturates spanned from the ultra fast-acting, medium, moderate, slow, etc. I believe the rule of thumb is that the more rapid the onset, the more frequent the potential for abuse (this is why Xanax is much more widely abused than, say, the slow-acting benzo Valium). With a more rapid onset, users perceive a much more powerful sense of a rush.
Barbs aren't used where I live I believe, and while they're still sometimes administered in different countries, if the barb isn't pheno it's one that's used to augment or ensure heavy sedation (analgesia) for instance. But I think most countries use them as infrequently as possible (though some still have their use). Many modern drugs other than the benzos have proved excellent at and even superior to managing, say, anxiety disorders (Pregabalin for instance), have much lower potential for abuse, and are more resistant to dependence and tolerance.
That's my general knowledge of phenobarbital and why it's still around when most of the others are either highly regulated or just absent. Hope some of this helped, but, of course, a doctor could tell you better.
Welcome again, and happy reading/writing.
