staying well fed like in real life helps also blue potions are very strong when it comes to restoring your stamina
as far as doing one damage is concerned you need to invest in combat or wis or whatever stat you are built for in nymphos case its constitution since if you don't overcome enemy armour you do one damage but i have a suggestion as far as like doing damage is concerned in the event you went the tough route, buy a saber it ignores armour and will be a good bedfellow for you till you reach about 30+ combat also losing stamina too rapidly is a sign you are fighting either unarmored or injured do not keep injuries around heal those with a red potion