Tips for new players accurate as a version 3.8... (and a question added for developer) question first to save the developers time. Why does a spell called drain not actually give the drainer the energy? That's how it works on final fantasy and every other game I've seen that ability on also rinny suggest it should be the same here but it doesn't recharge health at all.
Tips
Get stamina potions. Get empty bottles enter forest attack and defeat fairies out fairy dust in the bottles at work bench combine the fairy dust and the stamina potion to get stamina potion+ (recovers 20 stamina a potion) also increases the mystic ability by 3. Once you manage to get the hint about house special on the rocks fight and beat the female boss there to get a tech to recover 1 mp when guarding add gain 2 stamina (by attending medical class) and you can (if your resistance is high enough) block to regain health and mp, since you will continue to take attacks this rises your resistance and means you don't actually have to sleep when you are "Tired" instead sit gain stamina and recharge while growing stronger