I was creating some condition cards when I noticed that... (all quotes from the SRD)
You are dying if you have negative HP1, you have not stabilized and you are not conscious.
A dying creature is unconscious and near death. [...] The character must make a DC 10 Constitution check to become stable
You are stable if you have negative HP1, you have stabilized and you are not conscious.
A character who was dying but who has stopped losing hit points each round and still has negative hit points is stable. The character is no longer dying, but is still unconscious.
You are disabled if you have 0 HP or if you have Negative HP1, you have stabilized and you are conscious.
A character with 0 hit points, or one who has negative hit points but has become stable and conscious, is disabled.
What happens to a character who ends up in negative HP and conscious without having stabilized?
A note on Ferocity: Ferocity happens when you would end up being Dying, and it prevents you from being unconscious while still being Dying, which means this situation exists, but it's not clear if the HP loss is the one of Dying (and can be stopped by stabilizing) or it's just a non-stabilizable form of the same. It even goes as far as to say that you're still Staggered, but you were never staggered to begin with. Anyway, it looks like it has special exception-based rules and it's not trying to explain a general case.
- But less than your Constitution score, otherwise you'd be dead