to disturb  - molestar, perturbar, desordenar, inquietar, preocupar 

to disrupt  - trastornar, perturbar 

to worry  - preocupar, inquietar, preocuparse, inquietarse, angustiarse 

to upset  - volcar, derramar, perturbar, disgustar, inquietar, alterar, molestar, sentar mal a, trastornar, desbaratar (planes, etc.), derrotar (en deportes) 

to confuse  - confundir, enturbiar, enredar, complicar