My peer/ colleague said that I speak quietly and don’t have confidence in my voice

I am 22, training to be a medical professional. I was with a peer of mine who is also training, who’s 37, on the ward.

We were talking to patients, for me it was the first time. Afterwards, he asked me if I struggle with speaking to patients. He said I speak quietly and without confidence in my voice.

I’ve suffered with low confidence for a large portion of my life, I’ve been trying to improve , so this has been a big blow to my confidence. I ended up feeling rubbish that day onwards.

Just wanted to rant as it upset me. How can I speak more confidently ?