Something is wrong with the game. (Dark Souls)

Hello all, I decided the other day to remember the souls series and play the Remaster of this game (steam version), started for the thief, knocked the long sword, go with him. But I did not increases the damage done with the sword at the enemy, no matter how many titanite it is not invested, I damagel 26 units long sword, then came to the blacksmith pumped it up to +3 iiii... still 26 units, damage is not increased, I have 4 times tried again to play but this bug is haunting me,I even downloaded the game again, and the damage of titanite will no longer be, but the strength and agility he skalitsa normal, what could be wrong?