Eh, the instructor, unless having a off day sounds like they may be a little off base. Your first day at hospital ever, course you'll be awkward, unsure, all thumbs, etc. Instructor perhaps could give some helpful guidance instead of psyching you out with a "youre failing" speech on first day, a "here's what you need to improve on or you could be endanger of failing" talk would've been much more productive in my opinion.
With that said, dont take that & run with it or place blame on instructor here on out. You did miss important stuff, you recognize it and will correct,, shake it off, you can improve here on out. When in doubt proactively put yourself in front of instructor & ask their thoughts on what have you. They are there to check you off so of course will not be responsive when doing that, but should be open, to you know, teaching or giving direction at other times. And if they aren't, advocate for yourself by asking them direct questions about anything you need guidance in. Good luck.