Yeah, happens. Especially if you're not careful after a spinout. There's no use gluing it back together, even super glue won't work. There are some 5x5s that are more prone to breakage...I broke 3 with an old one, but haven't broken any with my current one.
So you can either buy another cube, use the old one for spare parts, or vise versa, or just order one from cubesmith for 1.50 plus shipping.