That sounds pretty shitty. Customer service can be the worst, especially when you get people in there who just seem to want to make your life hell. I mean, you'd think they'd take into account that you're just trying to do your job. But hey, this was just one bad night. Your manager will hopefully be reasonable and understand that things just snowballed and kinda got out of control. Maybe to make things go smoother in the future, you could give your coworker a crash course in punching in orders and stuff. It wouldn't just benefit you, it would help her later on. When you talk to your manager about it, just tell him very calmly and diplomatically what happened and assert that you are capable enough to handle night shifts, it just happened to be a bad night. It wasn't entirely your fault and I don't know anyone who could have handled that sort of stress perfectly.
Try not to get too down on yourself about it, okay? If you wanna talk, I'm here xoxo