The first thing we usually recommend when people have trouble with their iPads is to reboot it.
To reboot, hold both the power and home buttons until the white Apple icon appears. Note that the slide to power off notice may or may not appear and the screen will go dark. Just keep holding the buttons until the Apple logo appears.
Then, after a while, your home screen should reappear. Once that happens, see if you have the same problem.
Let us know how you get along.
Marilyn