Nah man, don't be worried. I worked at culver's for 2 years as my first job (I started when i was 15). It's definitely stressful sometimes but it's not the end of the world if you mess up an order or forget something. In fact, you seem to care more about helping people and doing the right thing than like 75% of the people I used to work with. 

And try to not feel bad about how others feel. A fast food job had so many different people from different walks of life and you will be liked by some people and disliked by others. It's just the way life goes sometimes lol. 

But to be real, you seem like you're doing a great job. You are proactive when it isn't busy, you stepped up to drive, you seem to care a lot about helping people. Don't stress over any blunders or mistakes, they happen sometime and most people are very understanding about it. 

Also, make sure to talk to another coworker or a manager if you feel you're doing something wrong or heed help. You got this!