Help!

I just got a job at an outpatient cancer center. I have only worked 2 days so far, but my second day on the job was a complete nightmare. There seemed to be too many people scheduled to begin with (more people than infusion chairs), and so I was told that they couldn't really take time to orient me that day, but just to help with vitals and such. I thought that would be fine, but it turned out to be a very stressful and overwhelming experience. Since I'm not chemo certified yet, I obviously couldn't help with that, but they had me doing injections, IV starts and then they showed me ONCE how to do a port-a-cath access/flush and then thought I'd be okay to do more on my own (after having someone watch me one time). I felt so lost all day - I didn't know where things were, didn't really know the paperwork part of it all or the computer stuff either. I'm afraid that if it's like that on my second day that I've got much worse to look forward to. I didn't have a chance to look up policy and procedure information before doing things. I came from the OR and so this is such a different type of nursing that I feel I need better orientation. I wanted to make this change for some time now and am so disheartened that it's not what I'd hoped. I honestly feel like calling tomorrow and telling them that I'm never coming back. I felt so "thrown to the wolves" and unsafe. I don't know what to do. If I quit so soon, I'm sure I'll burn my bridge to ever going back there... then again, why would I ever want to go back there?