Prius Dashboard lights came on when started at 0degrees Farenheit!!

Hello everyone,

Today in NY the temp in the morning was 0 d F. As I started up the car I hear a rough aggressive movement coming from the engine compartment then the Ready sign, beeping and the check engine light, (Giant red triangle ! Emergency sign), and the (!) sign.
I turned it off and one 3 times same thing, I decided to leave it and turned back home, then I noticed the battery level dropped to 2 bars from like 5 bars within 5 minutes. I did/was able to move the car back and then forth just to see if it would work, but the normal engine never came back on(on the computer screen), any thoughts on what might be going on?

I've read various threads that say that people have no problems at running their Prius at very low temperatures, so what might be going on here? Why today?

 

Nooo not the battery ((

 

Yes the dash says "READY" but the engine isn't heard and doesn't show to turn on in the screen. I also turned the heater on and within 1 second it turned back off.

 

What's that?

 

Oh yes definitely. So you're saying to call road side assistance? Because I think I'm not suppose to move the car from where it is.

 

Thank you so much for all the info, I forgot to thank you yesterday I was in such shock.
Today I went back out and performed a little battery test and it didn't stand within the accepted range of voltage, for the most part. Here are some pictures!
Try#1:
STEP 1: test voltage at MFD mode: (SHOULD be 12.4-12.8v as there's really no load on the battery) but I got 11.9v on the first try and 12.0v at the second try (not much of a difference).

STEP 2: test voltage at ACC mode: (SHOULD read 12.0v) but I got 11.5-11.6v.

STEP 3: test voltage at START "READY" mode: (should read 13.6-14.4v) this time I actually got 14.2v.

The engine started again thank God, and it charged the battery, I still have some of the lights on the dash including the major one (red triangle), I got the car to move because I had to move it from the zone it was at for street cleaning, but I'm still trying to figure out what to do next. Call road side assistance at least just to get the OBD to read the DTC.
Thank you guys so much for the help!

 

By the way the mileage is 175,700miles Prius 2004!
Maybe I should consider upgrading? :/

 

Did you see the pictures I posted? Do you know what the little orange/pink symbol on the top right corner of the display means?

 

Yes definitely, but considering that I am a student and part time worker anything is expensive haha. But if definitely love an upgrade even though I've come to love my Luna