Facebook App. Problem on my iphone 4G - please help?

[$prinkles]

I have a Facebook App. on my iphone and when I opened it a few minutes ago, the icons (profile, chat, photos, messages, events, etc.) started "shaking" like the way apps do on the iphone home screen. I instantly thought it was strange that this was happening within an app and then all of a sudden my "messages" icon disappeared in the facebook app! Does anyone have any advice as to how I can retrieve my message icon? Thank you!