Ah ah, welcome to the thing!
I guess that stamina's exact drain on action, and regeneration rate can always be adjusted in the future... but your playstyle seems nonetheless a little reckless? When I hear a troll, I stop everything, crouch and try and determine its direction and pace. Then, I try to snipe nearby dwarves, but if they are too numerous or too potent, I just retreat. Brutes don't seem to like running, thankfully. Also, perhaps you already killed the first boss, and just experienced a raid? In this case, any hostile will know you are here.