Ur not useless. And ur aiding in blessing the world with another life. Don't be so hard on urself. In addition to writing down good things about ur baby write down positive things about urself. Whether you quit or not is up to u & I'm not here 2 sway u one way or the other. I'm sure u are already aware of the dangers. My sis in law has 5 children and smoked with all of them. All 5 are healthy. Do what u can & don't beat urself up over what u can't.
Try writing down your feelings instead of smoking you'll feel a lot better and everything will be off your check also with anxiety try thinking about all the good things your baby could become to be and that should calm you down goodluck