Translation:You are depressed
I know that mfadhaiko is the Swahili word for depression (as a mental illness), but Jehovah's Witness texts use mfadhaiko as "stress" (and use (ugonjwa wa) kushuka moyo for "depression"). I think it's quite possibly something that's not yet fully standardised, either across dialects or, for example, common language versus medical jargon. As understanding of mental illnesses grows, terminology changes and things get redefined ... so there may be some ambiguity because of that??
Meanings of kufadhaika that are familiar to me are: to be troubled, to be confused, to be disturbed, to be dismayed or perplexed, to be agitated. None of these are in the context of mental health per se; I found them in stories, in sentences like Aliposikia habari hizo, mfalme akafadhaika sana. - "When the king heard this news, he was greatly troubled."
In addition to "You are drepressed" (if indeed "kufadhaika" is the word that has been adopted in Swahili medical terminology to mean "be depressed"), all of the possible meanings of kufadhaika (a word that has existed in Swahili probably for centuries) should be accepted as correct answers.
fadhaika verb - be confused / perplexed /dismayed /troubled / demented