For general severe confusion:
* Labis na kalituhan (literally "excessive confusion")
* Malubhang pagkalito (literally "serious confusion")
* Pagkalito na malala (literally "confusion that is serious")
For confusion with a more disoriented feeling:
* Pagkahilo (dizziness, but can also convey confusion)
* Pagkalito ng isip (literally "confusion of the mind")
* Pagkabulag ng isip (literally "blindness of the mind", implying a lack of clarity)
For confusion resulting from shock or trauma:
* Pagkabigla (shock)
* Pagkasindak (fear, terror)
The best term to use will depend on the specific situation and the level of severity you want to convey.