Daylight saving time

I went back home very late yesterday with my cell phone's battery dead. My cell phone is my primary source of knowing when, so I have no clue as of what the time really is. After I recharged the battery, I did notice that the time on the cell phone is one hour off compared to the time showing on the computer. I didn't consider the possibility of daylight saving time change though. The only thing I thought was that the backup battery in my cell phone also died, which causes the time change. The next day I woke up at exactly the same time as before without noticing that the duration of my sleep was actually shortened. Hmm. This probably means that my schedule is too irregular.