My display shows that Nav disc is missing..its not the case

[elvism]

for sure.. i recall it being on earlier in day and then i stopped at a dunkin donuts for a coffee.. i started up my car looked at my screen and on right side(sm window) of my screen i always have nav on..this time it should vehicle info...i then put nav on big screen and it says please install disc..10 minutes later my seat belt was ringing to notify me that i need to lock up my belt.. i had it on..the bell stopped after 5 times...but nav still says samething.. i pulled over and shut off the X.. pushed eject on nav but nothing.. i then tried to put in a regular cd in nav slot but it wouldnt take it...what gives? no way someone broke in and took my disc..i was in DD for 2 minutes and i always look my doors...what gives?