Try to sing notes that you feel comfortable singing at any volume. Notice how you go high in the voice or your throat feels like it's constricting, closing up tight. It appears that you can't sing the notes loud or at all when you go to too high of a range for your voice.
Adjust your body so you sing with the support of your diaphragm. Muscular structure, called a diaphragm, envelopes the lungs. The area of the diaphragm also involves the ribs, lower sides, bottom and back.
Place your finger near your mouth and breathe out. Feel how fast the air comes out. The air needs to come out slower and more evenly.
Use your diaphragm to support your breath by pushing down with the diaphragm against your ribs. Let the air out of your lungs slowly. Feel the air come out slowly on your fingers. Practice this a few times.
Try to sing the notes using your diaphragm as support. Take in air through your nose and relax as you sing your notes pushing the diaphragm against your ribs.
Sing so people hear you, and that requires confidence and willingness to be heard.