Ask the Recruiter

You'd be surprised how many people struggle in their first days on the job, and you can't always tell how successful someone is going to be in the long run by how they start out. People learn in different ways, and it sounds like whatever training you were given didn't necessarily click with your way of learning. In any case, I can give you three pieces of advice:

1. Slow things down. Even if the work environment is hectic, find a pace at which you can work without mistakes. Your pace will increase naturally over time, but if you keep making mistakes by trying to go too fast, you will just get flustered (and possibly fired).
   
   
2. Get your supervisor on your side. Request a meeting with your supervisor. Use that meeting to calmly and rationally explain the problems you are having, and then ask for suggestions. Face it, the supervisor already knows about the mistakes you are making, but putting it on the table professionally show that you acknowledge the problems and want to work constructively toward solving them. Also, asking someone for advice can put them in your corner, as opposed to them feeling like an adversary.
   
   
3. If the job doesn't fit, then quit. If you try these steps and still aren't making progress, make a change. Learn from the experience, so next time you can choose a job that is better suited to your skills.