Is reheating food necessary

I know this may be a silly question but this is a silly question.

Is it necessary to reheat food the same day you got it? My bf and I ate food and left it in the car while we went grocery shopping and then came home. I was so hungry and started eating the leftovers without heating it up. I'm 15 weeks pregnant. First time mom so I'm just being cautious. Google is my worst enemy so I just need advice from people who just eat leftovers with no problem! Thanks!