You need to go inside the Sanctuary and talk to the NPC's. They'll heal you up, and I'm assuming that the Black City isn't so abandoned that they don't have NPC's manning the basic facilities... But that's Windel's call, not mines.

So [@Unlucky0013] you might have just gotten healed by a Player posing as an NPC, and the Sanctuary might not be active. Otherwise get ready for more Outlaws swarming your position, cause a lot of them just died.