Kenya trees are a type of leather. All leather corals periodically go through a phase where they sag and wilt, basically look like crap, and shed their mucous. It sounds like that's what's happening to yours. It's perfectly normal, and it should snap back in a week or so.
I would recommend that you not keep a kenya tree coral. They are commonly sold to beginners as "easy" corals, but that's the problem. They reproduce and spread very quickly, and can easily take over a whole tank, smothering out and killing other corals. And once they are out of control, there's no easy way to get rid of them. In my 240 gallon tank, my whole tank was eventually overrun by what started as one kenya tree. I ended up having to boil 600 lbs of live rock on the stove (killing it) just to get rid of the kenya tree. And that was after it had killed over $1000 worth of corals.