My Nikon D5000 fell from about 4 feet high

While I was asleep my Nikon 5000 fell from around 4 feet into the floor and my 18-55mm lens came apart, now I was furious with my sister who some how she was in my room while I was taking a nap or so, so I'm checking it now, but looks like it's alright still takes pictures but I'm a little worried as to which my mind has already the thought that something isn't right. It's my first drop and I'm a little worried it might not function right, the eyeview is a little loose. Might have already been like that but it doesn't bother me, the inside is what matters the most for me the mirror what are some things I can check to make sure nothing is damaged, and if anyone knows. How long does a DSLR last if it's dropped?

Added (1). Actually when I attacked the lense if I hold it down and lean it to the side, the camera makes a "click" sound and when I look in the eye view it's a little dark.

"the eyeview is a little loose" - that's not a problem, just take it off and replace it with a new one, or try the paperclip trick: (wrap a thin wire, thinner than a paper clip around the place where the eyepiece slides in. Then slide the eyepiece back on.it'll stay there for a very long time)

don't worry too much about it. You should be fine. If the mirror is not broken, then chances are, very few other things are.

However… DO check for debris from the lens in the body to make sure nothing gets jammed. Don't use it until you're sure there's nothing inside the mirror mechanism/ sensor. Clean the sensor with one of those giottos blowers. And you should be fine.

As long as those two things are okay, you should be able to take pictures without a problem.