Honestly, without stamina potion, once you're in downed state you're DONE.
Conserve your stamina, learn to RUN and use this QOL little mod I requested from Teravisor :
https://f95zone.to/threads/lonarpg-v0-4-8-0-eccma417.49993/post-4929958
But that only is an option when you're out of combat, isn't it? I can't really go to sleep while an enemy is attacking me, and since none of the attacks seem to work while you're down I don't see how you'd ever get out of the downed state...
you can do it mid combat as long as the enemies doesnt strike u while u resting, which is why u always need a companion with u to distract enemies so u can actually do that, i cant stress this enough for newbies to learn there strength in number and Lona a weak peasant girl she need all the help she can get. secondly killing enemies doesnt yield any exp at all unless it needed specific for the quest Lona should avoid all conflicts, the chances of enemies actually drop usable item for her vs the amount of resources, effort, and luck to survive the fight is not worth it.