I parked my car late Friday night and after I turned it off I noticed a red blinking light on the dashboard under the speedometer of a car with a lock next to it that I hadn't really noticed before. I looked online really quickly and many other questions similar to it pointed to it being an immobilizer and that it was normal and nothing to worry about. I'm a college student and don't drive often so I finally came to my car today and it wouldn't start and or unlock using the key fob and I assume that its the battery that's dead since the ignition wouldn't even fire.

I plan on calling AAA to get a new battery on Friday since that is the earliest I have free time. But for the future, I know that I turned the lights off so the only thing that I can think of that drained it was the red light, although I find it hard to believe that the little red light flashing every few seconds drained it. I am a little stumped. Is there a way that I can turn it off or make sure that it isn't taking up so much energy in the future?

 

Nothing to worry about that immobilizer light.
Just make sure you lock the car with the remote after, as well as turning off lights and closing glove box.
It is getting colder. I have no idea why you didn't say how old your car was as this is important info.
Get a new battery and wrap it in insulation! The insulation will keep the heat off it (heat kills batteries, heat from engine) and it will help keep the cold off of it, making for easier starts.
Clean your ground at the body as well.

 

Thanks for the replay. I can't believe I left out the year. Its a 2012 Mazda 6 so there's no reason why the battery should be broken. Its also been consistently 45-70 degrees out here on the east coast in the US so the could shouldn't be much of a factor. Maybe I did leave a light on, must have made a mistake. Thanks for the help, I'll be sure to take your advice.