Q: It was 30° outside last night and my car shut off while driving now won't turn, on please help.

Last night was about 35° outside and I didn't warm the car because I was In a rush so I just turned the car on and about a min later I reversed out of parking space and then proceeded down the parking lot to a stop but as I was about to stop the car felt like it was loosing power like it wanted to stall and as I was slowing down the car shut off and I tried to turn it on but nothing I even gave it jump and nothing and today I took the battery to get tested and the battery was tested good in voltage and cca. I checked the fuses and everything is good. Can I mention the timing belt was raddleing but since 2months ago. Idk if that has anything to do with it. could it have broken off or something. I could really use Some help figuring out what it is. Thank you

My car has 156321 miles.
My car has an automatic transmission.