My Timezone keeps changing...

[stanglifemike]

Ok, sorry if this has been discussed already but I havent been on here a lot recently so I may have missed it. My timezone should be Eastern but keeps changing to Central. Sometimes it wont change for a day, sometimes I set it back to Eastern and 5 minutes later it jumps back to Central while I am still in the same room and my phone is sitting untouched. It has already caused me to be late to work due to my alarm not going off on time, and G-Alarm is the only alarm clock that I use.
What would/could cause this? Quick GPS is up to date, I have already tried switching from Global to CDMA but still nothing.