You will have to train yourself on breath control, playing any wind instrument is not easy cause you are breathing unnaturally. You use your mouth to control your breathing, when it is time to exhale, you don't just breath out, you have to blow the air out. While playing, it is best to remain standing rather than sitting down. Your stomach and respiratory muscles are relaxed while standing.
If you prefer to sit, make sure your thighs are downwards so your stomach is not bent. Try not to lean on the chair so your thighs are not upwards. How you use the mouth piece can also determine how comfortable your breathing will be. With much practice and training, you will begin to play with much ease.
All humans need to breathe. The act of playing an instrument involves constantly exhaling so running out of breath is natural. However, there are a few quick things you might can adjust to ensure you're inhaling and exhaling as much air as possible. The first is sitting up straight. This allows your lungs to fully expand their capacity. Next is the belly breathe. When you breathe with your belly or diaphragm, you are able to suck in more air.
Finally, don't move your shoulders when you're breathing. Shoulders should stay in place and not rise and fall like you're trying to catch your breath from running or a dramatic cry.