Yes, you can suffer consequences for not attending a meeting at work. Work meetings are scheduled so that the business can operate with everyone knowing what is expected of them and therefore, for the business, those meetings are ultra important to keep the business running smoothly. Just like your education is important to you, those meetings are the main focus of the business. When employees are not involved with important meetings, it shows that you do not take your job seriously and rather than fire you, you are reprimanded by losing a shift/a night's pay.
You should have rescheduled the meeting with your school so you could attend the job meeting. But, you chose not to and you are paying the consequences. This is a tough lesson to learn, but that is EXACTLY why you are being punished. Do not miss another work meeting. Arrange your education around your job and if you can't, then you will lose your job. Meetings at work are mandatory and you need to attend them if you want to keep your job.