I'm a 33 year old woman and I quit smoking about 2 weeks ago. Now all of a sudden I've started feeling very short of breath all the time. I'm sighing a lot and yawning to try to get deep enough breaths. I didn't have this when I was smoking, so I don't think it's related. If I lay down, after a while I feel fine and have no trouble breathing at all. Last night, when I went to bed, my heart was beating really hard, until I got to the point that I could breathe, which seems to take a few minutes. But once I'm breathing well, it stays that way until I get up again. This is driving me crazy, not being able to breathe. Any activity has me winded, I don't have to exert myself at all. I'm not gasping for air, but I'll breathe a couple of times and then I have to sigh, as deeply as I can, to try to get air, or I have to yawn or something. Yawning is frustrating because I can't yawn deeply enough to feel satisfied. I sigh every few seconds just to feel like I am filling my lungs. I can't take a deep enough breath through my nose at all unless I am in bed. I'm so worried about this! What is wrong with me???