How to be confident as a Nurse when it comes to talking to families on the phone?

[Convoy2022_TrumpSupporter]

I am a new Nurse and I am a bit shy talking on the phone since sometimes I may not know what to say. In my Nursing Home families cannot visit their loved ones cause we have cases. Sometimes families get mad at me and I take it personallyy like if their dad has a fever and I gave them Tylenol, put a cold cloth on their forehead, yet these families expect a miracle from me, but they act oblivious that their parents are old and aren't themselves.