[daplatapus]

That's too bad. But I understand how you feel. I've seen people like yourself have a hard time when doing my dive master training. And I think it's completely understandable. Breathing under water isn't exactly natural.
Pushing yourself to do something like this or to go along with the group, ignoring your fear, may put yourself and others in danger so be careful of peer pressure and how you are feeling.
I'd see if you can get some extra time with an instructor to just go down and lay on the bottom of a pool and just sit there breathing. Nothing to do, no drills, or skills training, just sit there and try to calm down. While sitting there, close your eyes and just concentrate on breathing. The more you do something, the more natural it becomes. And you may just need some extra time getting used to working at breathing underwater without having to follow a class and keep up with everyone else at the same time.
There wasn't enough details in your original post, but I'm surprised that with the difficulties you were having and the amount of air you went through, one of the instructors didn't come over and see if you needed some one on one help. Maybe approach one of them and explain the difficulties you're having and if they're un-sympathetic, you may need to look for a different training facility.

Sorry this first experience was a bad one. The ocean is a wonderful place to explore and relax. I hope you can find someone to help you overcome your initial fears.