Hi there,
Current nursing student here!
I am sorry that you're having a bad experience, and upon reflection of the NMC Code and my practice document, the only issue low confidence would bring would be an inability to speak up about issues, be it with staff or for your advocating for your patients. Another example would be if you were unsure about medications, which have the potential to cause an issue. However, if you're competent in both and feel this is just a personal attack and that this is not a true reflection of your practice, I highly recommend contacting your Practice Education Facilitator or the appointed members of staff for placement at university, and doing so as soon as possible.
Hopefully this gets resolved for you
Nat