I just got a big 1yr persian cat yesterday and it lays around all day. i havent seen it eat or drink water yet! i know it has to adjust to the family but why is it acting like that?

ever since i brought the cat home she has been laying around. she just got out of the running and hiding stage, but i havent seen it eating or drinking its water yet. im concerned. i dont want her to get sick and die. can someone please help ease my mind?