Training too much to fast?

Recently, I started a new job at a pysch facility. This is very different from anything I have done before and for me is a big transition from computer charting back to paper. The facility has a week of orientation that includes a lot of HR stuff, CPR and a day of training on restraints and confrontation. There was maybe a day and a half of nursing training. I Got to shadow on the floor for four days and went to three units in this time. My first day off shadowing they had me do meds for 21 patients even though I never shadowed with a med nurse. RN don't normally do meds and I tried to watch the med nurses but had no idea I would actually be doing this. I made it through and everyone got all their meds but I don't feel like I did a very good job. I've been there a little over three weeks including orientation and have done either a different job or have been a different unit every night. I did finally get to shadow with a med nurse but that was on a forth unit. This whole time none of the supervisors have checked in with me to see how I am doing.

When I took the job they made it sound like I would be primarily on one unit and I had no idea I would be expected to do this many jobs this quickly. At this point my head is spinning and I don't feel like I'm doing a very good job. All of the units have different rules most of which are not written down. Things are also in different places on each unit. Since they are still 100% paper charting this includes all the forms...

To me it feels like the expectations are not reasonable but since apparently everyone who works there went through the same thing I'm wondering if it's just me? Any thoughts or advice would be appreciated as I am feeling very stressed out.