Are you sure you're not stuck in walk mode instead of run mode? (When you're in this mode, movement buffs have no effect). When Walk Mode is active, there will be an icon of a pair of legs in the top corner next to the clock and connection info. Walk mode and run mode can be switched between on the keyboard by tapping the '/' or 'R' keys (I'm not sure of the equivelant for controller I'm sorry), so it's actually quite easy to accidentally engage without realizing.

Welcome to Eorzea in any event!