Hi there!
I’ve just bought the complete edition of the game; after that, and reaching level 60, killed a crocodile and took a potion that resetted all my stats; my inventory is EMPTY and my weight capacity is 99%, even with 20 points in Strenght. What happened? Can’t play anymore! Thanks!
You do get a small amount of encumbrance from Strength, but most comes from your Expertise attribute (see wiki for details). When you reset your stats, the armor you were wearing likely became too heavy for you. Put some points back into Expertise and continue enjoying the game. 
BTW ~ Welcome to the forum! 