When playing Nethack, I have several times now received this message "Not enough stamina to move" typically when a monster is standing right beside me. >.< What does this mean and how can I fix it?
To solve this overburdening requires dropping heavy items, putting them somewhere that they weigh less (bag of holding), or increasing the amount you can carry (increase your strength or constitution).
Learn more! Nethack Wiki on Encumbrance