iPad 2 help freezing and not responding.?

so my ipad is being extremely slow & unresponsive. I got it a month before the iPad 3 came out. I have the iPad 2 white in 16gb I do know I have no storage left? I actually was planning to get the iPad mini 64gb + cellular but it doesn't have a retina display. /; so I my warranty expires the 30th of this month I don't know if I should go to the apple store and get it checked out. I don't want to look stupid because if its because that I have no more storage. help help help. it has trouble loading the built in apps like music and messages and randomly freezes while im using it also when it freezes I have to reboot it because it wont do anything and if I turn it off it will still be laggy after turning it on.