It just takes time. I went through a similar thing myself.
8/6/1994 I was in a horrible head-on collision. My injuries were (starting at the top):
Broken nose, broken jaw, part of my bottom lip was cut off, part of my tongue was cut off, whiplash, several broken ribs, punctured lung, two cracked vertebra in my lower back, left femur (large thigh bone) broken in the neck (where it goes into the hip) and broken mid femur, right femur was dislocated, left hand was crushed but not broken, right hand was broken in three places and dislocated in another - I think that's it.
Because I had the puctured lung, I had a chest-tube due to a pneumothorax also. While I was still in the hospital, they had me breathing in (enhaling) into a device that exercised my lungs and helped me to increase my ability to breath deeply. I don't remember what it was called. It's made out of plastic and it is clear and blue. It has a blue plunger -type thing on it that goes up (or down - don't remember exactly) when you enhale. Measurements on the side indicate how deep your enhaling breathe is. They gave it to me to take home after I got out of the hospital. After a few months of several daily breathing exercises, I was able to breathe normally again.
It's frustrating while you wait to get well. The nice thing is that you are actively involved in your progress when you use the device I mentioned. I just wish I knew what it was called. It's been so long ago now.
I hope you're feeling better really soon,
Roberta